Ground Ivy

What is Ground Ivy?

Health Canada's oral monograph for ground ivy (Glechoma hederacea), dated January 30, 2026, allows only "traditionally used" claims, and none of the references it cites is a clinical trial. No clinical trial of the herb taken by mouth was located for this issue, and that absence shapes everything below.

Glechoma hederacea is a creeping perennial in the mint family, Lamiaceae, native to Europe and temperate Asia. It roots at the nodes of square stems, carries kidney-shaped to heart-shaped scalloped leaves 2 to 4 cm across, and flowers blue-violet from about April to June. It reached North America with European settlers; the US Forest Service's Fire Effects Information System review (Waggy, 2009) cites a first report from the northeastern United States in 1672, and it is now a lawn weed across much of the continent. The plant is gynodioecious: some clones carry only female flowers, and in Swedish field work by Widén and Widén (Oecologia, 1990) a female clone isolated by more than 200 m from any hermaphrodite set no fruit at all. Herbal products use the dried flowering aerial parts.

East Asian medicine uses close relatives. Japanese kakidoushi-cha is a folk tea made from G. hederacea var. grandis (sometimes treated as the species Glechoma grandis), and Korean and Chinese studies often use G. hederacea var. longituba (also named Glechoma longituba). In the Chinese trade the plant has also been sold as "Jiangsu jinqiancao," one of several regional herbs marketed under the name jinqiancao, whose pharmacopoeial species is the unrelated Lysimachia christinae.

Common Names

Ground ivy, gill-over-the-ground, gill-go-over-the-ground, creeping Charlie, alehoof, tunhoof, cat's foot, field balm, haymaids; Gundermann or Gundelrebe (German); lierre terrestre (French); hondsdraf (Dutch); kakidooshi (Japanese, var. grandis); lianqiancao (Chinese, for the longituba form). It is not an ivy: true ivy is Hedera helix, in a different family, and "ivy leaf" cough syrups contain Hedera, not Glechoma.

Primary Active Compounds

Phenolic acids lead by weight. Rosmarinic acid and chlorogenic acid dominate: in Latvian field trials, Sile and colleagues (Plants, 2022) measured 5,105 micrograms per gram of rosmarinic acid and 3,390 of chlorogenic acid in extracts of flowering shoots harvested in 2021, against 3,218 and 1,461 in vegetative shoots. Caffeic, neochlorogenic and cryptochlorogenic acids are also present. Flavonoids include rutin, hyperoside, and glycosides of apigenin and luteolin; free apigenin and luteolin appear only in flowering shoots (97.0 and 39.5 micrograms per gram in that study). The triterpene acids ursolic and oleanolic acid are concentrated in the leaves, where Grabowska and colleagues (Planta Medica, 2021) measured ursolic acid at 7.1 to 7.5 mg per gram of dry weight. A small essential oil fraction (0.03% to 0.3% of dry weight in the Latvian study) has main constituents that include β-myrcene, β-ocimene and the sesquiterpene germacrene D. The leaves also contain a lectin, Gleheda, and the whole plant yields sesquiterpene lactones described by Kim and colleagues (Planta Medica, 2011).

Key Note

Ground ivy carries three inherited warnings: that it poisons horses, that it contains the liver toxin pulegone, and that it removes lead from the body. Each is examined below against what was actually measured. The short version is that the first rests on textbook descriptions with no documented outbreak record located, the second rests on an old qualitative listing rather than a measured amount, and no study located has tested the third.

Ground ivy is a mint-family herb with a long folk record, solid phytochemistry, and one small cosmetic trial on skin.

Scan any Ground Ivy product in seconds with the free NutrientWise app: App Store · Google Play

Primary Functions & Benefits

Ground ivy's reputation is as a respiratory, digestive and "cleansing" herb. King's American Dispensatory (Felter and Lloyd, 1898) called it "stimulant, tonic, and pectoral" and listed lung and kidney disease, asthma and jaundice among its uses. Health Canada's 2026 oral monograph licenses traditional claims as a stomachic to aid digestion, an expectorant and anticatarrhal for coughs and bronchial complaints, an astringent for diarrhea, a diuretic, and a remedy for hemorrhoids. Its separate topical monograph (October 30, 2018) allows "Traditionally used in Herbal Medicine to help heal minor cuts and wounds (vulnerary) and to help soothe inflammation." In Chinese and Japanese practice the related varieties are used for urinary and gallstones, jaundice and skin sores; the urinary claims belong to another issue and are named here only.

Skin pigmentation: the one human trial

Ha and colleagues (European Journal of Dermatology, 2011, volume 21, pages 218 to 222) ran an 8-week, double-blind, placebo-controlled study of a lotion containing 1% ground ivy extract on UV-induced pigmented spots in female Asian volunteers, and reported significant anti-inflammatory and depigmenting effects. The abstract does not give the number of participants, and the full text could not be retrieved for this issue. The laboratory background is consistent: in mouse B16 melanoma cells, a ground ivy extract lowered melanin content and tyrosinase activity without obvious cytotoxicity (Qiao and colleagues, Bioscience, Biotechnology, and Biochemistry, 2012). A cosmetic lotion result says nothing about swallowing the herb.

Liver and gallbladder, in rodents

In rats with surgically ligated bile ducts, daily oral hot water extract reduced markers of liver injury, inflammation and fibrosis (Wang and colleagues, Journal of Ethnopharmacology, 2017). Xiao and colleagues (BMC Complementary Medicine and Therapies, 2021) tested Hitrechol, a German ground ivy extract capsule, in mice fed a gallstone-inducing diet for 3 weeks, with 4 to 6 mice per group. Three-times-daily dosing reduced gallstone crystals, bile cholesterol and liver necrosis; once-daily dosing did not significantly lower bile cholesterol. In rats, the extract did not significantly change bile flow over 2 hours (6 per group). The authors wrote that "several clinical studies" have shown ground ivy extracts can decrease gallbladder complaints, citing a reference that could not be retrieved for this issue; no such trial was located in PubMed.

Inflammation and bone, in cells

Ground ivy extracts suppress inflammatory signaling in isolated immune cells. An and colleagues (Journal of Ethnopharmacology, 2006) found that an extract inhibited nitric oxide and TNF-alpha production in stimulated mouse macrophages. In the Latvian study, 70% ethanol extracts at 500 micrograms per mL reduced the conversion of mouse macrophages to the inflammatory M1 type by 13% to 56%, depending on harvest. Hwang and colleagues (Journal of Dental Research, 2014) showed that an ethanol extract blocked the formation of bone-resorbing osteoclasts in culture, which the authors suggested could be relevant to gum disease (periodontitis). No study in a human mouth was located.

Antimicrobial activity

Steam-distilled whole-plant oil from Vietnam inhibited Staphylococcus aureus, including MRSA, and Candida albicans at roughly 1 to 8 microliters per mL, and had no effect on Escherichia coli or Pseudomonas aeruginosa up to 32 microliters per mL (Nguyen Van Phuc and colleagues, Journal of Medical Research, Vietnam, 2024). A methanol extract inhibited multidrug-resistant clinical isolates at 62.5 to 500 micrograms per mL, and a 5% extract hydrogel reduced bacterial counts in infected rat skin wounds (El-Aasr and colleagues, Natural Product Research, 2022). These are dish and rat results.

Lead colic and "heavy metal" claims

The lead story is the strangest in the herb's file. King's American Dispensatory (1898) said an infusion of the leaves was highly recommended for lead colic, the abdominal cramping of chronic lead poisoning that was an occupational disease of house painters, and claimed that painters who used it often were never troubled by it. The USDA's 2013 plant guide for ground ivy (Pavek), citing Durant's 1976 book on plant names, repeats that ground ivy "was also given to painters to treat 'lead-colic'." No study was located that measured blood lead, urinary lead or lead excretion after ground ivy in any species, and none of the pharmacology papers reviewed proposes a mechanism. The modern "heavy metal detox" phrasing in online herbal writing has no source beyond this folklore. If anything, the plant takes metals up rather than removing them: a Warsaw study (Wojtkowska and colleagues, Environmental Monitoring and Assessment, 2015) sampled ground ivy as one of the dominant plants growing on a heap of copper and cadmium contaminated pond sediment to study bioaccumulation. Lead poisoning is treated with removal from exposure and, when indicated, prescription chelation.

Ears, sinuses and tinnitus

William Salmon's Botanologia (1710) said the juice "put into the Ears, it helps the Noise in them, as also their Ringing and Deafness." Gerard's Herball (1597) recommended it for tinnitus, and King's (1898) reported that the fresh juice snuffed up the nose was said to cure headache. Current herbal writers still promote it for catarrh and noise-induced tinnitus. No controlled study of ground ivy for tinnitus, hearing loss or sinusitis was located. Mullein owns the ear-oil story in this archive; nothing should be put into an ear with a perforated eardrum or an infection without a clinician's examination.

Forms & Standardization

No standardized ground ivy extract has been tested in an oral human trial, so nothing on the shelf can be measured against a tested benchmark. What exists is a set of preparations whose chemistry depends heavily on the solvent.

Dried herb and tea

The form Health Canada's oral monograph covers: dried herb top, cut or powdered, taken as an infusion or decoction, or as a non-standardized extract made with ethanol, water or both. Grabowska and colleagues (Plants, 2022) showed why the solvent matters. A water extract made by infusion combined with maceration yielded 4.28 to 4.89 mg of rosmarinic acid and 3.41 to 3.70 mg of chlorogenic acid per gram of dry herb, while an ethanol extract made the same way yielded only 1.07 to 1.14 mg of rosmarinic acid. Ethanol under heat reflux pulled out more rutin and isoquercetin (up to 0.99 and 0.96 mg per gram). For the phenolic acids, a plain tea is the more efficient preparation.

Tinctures and glycerites

Alcohol tinctures and alcohol-free glycerites are sold by small US herbal brands and rarely state a marker content. Hawaii Pharm's alcohol-free product is a typical example: its label calls it a "Dried Herb ALCOHOL-FREE Liquid Extract" made from dried aerial herb in a base of 60% vegetable glycerin and 40% water, lists "Ground Ivy (Glechoma Hederacea) Dry Herb extract 1156 mg" per 1 mL serving without saying whether that figure is herb weight or extract solids, and gives no herb-to-solvent ratio. Its directions are 20 to 30 drops (about 0.7 to 1 mL) in water up to 4 times a day. Its warnings say not to use it during pregnancy or while nursing, to avoid it with a kidney condition, not to combine it with "pulegone-containing herbs, such as pennyroyal," and that the plant is regarded as toxic to horses. Glycerin is a weak solvent for the triterpenes and essential oil, so a glycerite is mainly a water-soluble phenolic preparation.

Capsule extract in oil: Hitrechol

The only branded ground ivy medicine with published chemistry located for this issue is Hitrechol (named Hitrechol Aihuo Dantong in the study), made by Pharmazeutische Fabrik Evers in Germany. According to the 2021 rodent study, for which Evers supplied the capsules, the dried herb is cut to about 1 cm, extracted at room temperature with 90% ethanol, concentrated under vacuum and mixed with sunflower oil in a soft gelatin capsule. The batch specification set ursolic plus oleanolic acid at 40 to 150 micrograms per capsule and linolenic acid at 70 to 350 micrograms per capsule (the paper's discussion section assigns these ranges differently). The authors state the product has been used for cholesterol gallstones since the 1970s. A capsule holding well under a milligram of its marker triterpenes is a very different object from the dichloromethane extracts Grabowska's group made, which reached 17% to 25% ursolic acid by weight.

Essential oil

Ground ivy is a poor oil plant. Charles Ridgway's analysis (American Journal of Pharmacy, 1892, as reported in King's) found 0.06% volatile oil. Sile and colleagues measured 0.32 to 2.98 mL per kg of dry herb (0.03% to 0.3%), against more than 6 mL per kg for chamomile, 8 for peppermint and 24 for sage. The oil is not a standard article of commerce, and its composition varies by origin (detailed under Toxicity Symptoms).

Homeopathic mother tincture

The French Pharmacopoeia monograph "Ground-Ivy for Homoeopathic Preparations" is the sole official quality specification located for European G. hederacea located for this issue; Chinese sources define the herbal drug Glechomae Herba (lianqiancao) as the aerial parts of G. longituba. The French text requires the whole, fresh, flowering plant, extracted with 45% ethanol; identity by thin layer chromatography against caffeic acid, chlorogenic acid and rutin; foreign matter of no more than 5%; and a minimum content of total hydroxycinnamic derivatives, expressed as chlorogenic acid. Homeopathic dilutions made from the tincture contain essentially none of it.

What the trials used

The one human trial used a 1% extract in a lotion, on skin. The rodent studies used hot water extracts (Wang, 2017) or Hitrechol's oily ethanol extract (Xiao, 2021). No controlled study giving any of these preparations by mouth was located, so no form can claim to be "the clinically studied one."

Food Sources

Ground ivy is itself a food plant in a small way, not a nutrient found in other foods. The young leaves are cooked as a vegetable, added to salads, used as a bitter seasoning and brewed as tea; a 2023 Polish paper (Sławińska and colleagues, Nutrients) notes "gill tea" in England from the 18th century, its use as a spice in egg, potato and cheese dishes, and occasional use by breweries as a bittering agent. In Japan the dried leaves of var. grandis are drunk as kakidoushi-cha.

What the leaves contain

Šeremet and colleagues (Foods, 2022) analyzed 7 samples of wild ground ivy from 6 Croatian localities, harvested in April 2020. On a dry-weight basis, insoluble fiber made up 32.26% to 48.03%, soluble fiber 4.97% to 9.14%, protein up to 23.12%, minerals 9.20% to 10.98%, and fat no more than 2.80%. Potassium ran 14.49 to 29.80 mg per gram and calcium 7.78 to 14.89 mg per gram. Arsenic, cadmium and lead were all below the WHO limits for medicinal plant material cited by the authors (1.0, 0.3 and 10 mg per kg). Microwave-assisted water extraction recovered up to 18.69 mg of rosmarinic acid, 7.15 mg of chlorogenic acid and 8.83 mg of rutin per gram of dry herb, depending on the site.

What a realistic serving delivers

A cup of tea from 2 g of dried herb, at the Croatian potassium range, contains roughly 29 to 60 mg of potassium if all of it were extracted, against an adult adequate intake in the thousands of milligrams. At the rosmarinic acid levels measured in the Polish infusions (about 4.3 to 4.9 mg per gram) and the richest Croatian extract (18.69 mg per gram), the same 2 g yields roughly 9 to 37 mg. Ground ivy contributes nothing nutritionally that a diet of vegetables and kitchen herbs does not already supply.

Cooking and processing

Drying concentrates the herb and, in a 1989 study (Kühn and colleagues, European Journal of Biochemistry), air-drying sharply increased the leaves' content of a hydroxylated fatty acid formed by lipoxygenase. Hot water favors the phenolic acids; water heated to 200 °C under pressure (subcritical water extraction) recovered significantly less of them and produced a new, unidentified antioxidant in the Croatian study. Gathering for the table carries a practical risk: ground ivy is a lawn weed, and lawns, roadsides and verges are where herbicides and traffic-derived contaminants accumulate.

Who Should Take Ground Ivy

No group has been shown in a trial to benefit from taking ground ivy by mouth. The realistic candidates are:

• Healthy adults who want a traditional bitter tea for occasional indigestion or a productive cough, understanding that the evidence is centuries of use and Health Canada's traditional-use licensing, not trials.

• People curious about the skin-lightening result, who should note that it came from a 1% topical lotion in one 8-week trial, not from capsules.

• Herbal practitioners using it within a formula, who should name the species and plant part.

It is not a substitute for medical care in any situation the folklore names. Lead colic is lead poisoning and needs blood lead testing; gallstones with pain, fever or jaundice need imaging; tinnitus of new onset needs a hearing assessment.

Who Should AVOID or Use Caution

Contraindications

• Pregnancy. Health Canada requires a consult-a-professional statement for pregnancy; consumer drug references (WebMD, RxList) rate it "likely unsafe" or "unsafe" in pregnancy on the grounds that it might cause miscarriage, and Hawaii Pharm's own label tells pregnant women not to use it, citing a traditional reputation as an abortifacient. No human or animal reproductive study was located, so the reputation is neither confirmed nor refuted. Avoid it.

• Breastfeeding, for lack of any data.

• Children, for lack of any data; the only pediatric tradition located (a Japanese folk tonic for weak children, made from var. grandis) has never been studied.

• Known allergy to ground ivy or other mint-family plants.

Use Caution

• Kidney disease. The consumer references above advise people with kidney problems not to use it, and Health Canada makes products supplying 200 mg or more of dried herb a day print the warning "diuretic effect may occur" unless their stated use is already diuretic.

• Liver disease. The same references advise against it because it contains a constituent that can harm the liver, and RxList states that larger amounts can cause serious liver damage. The pulegone they point to has never been measured in ground ivy (see Toxicity Symptoms), and no human liver data exist either way.

• Epilepsy. RxList advises people with epilepsy or a history of seizures not to use it, without giving a reason. Pinocamphone and pulegone, both listed among ground ivy's oil constituents, are among the monoterpene ketones blamed for essential oil seizures (Burkhard and colleagues, Journal of Neurology, 1999), which is a plausible basis. No seizure attributed to ground ivy was located, and neither was any study designed to detect one.

• Combining it with pennyroyal (Mentha pulegium) or any other pulegone-rich herb or oil.

• Anyone with symptoms that the traditional uses describe (persistent cough, diarrhea, jaundice, bleeding hemorrhoids) should be assessed before self-treating.

Critical Safety Point

The only toxicity record for ground ivy concerns horses, not people, and even that is thinly documented (see Toxicity Symptoms). For people the risk is unmeasured rather than shown to be low. Concentrated ground ivy essential oil has never been safety-tested for oral use and should not be swallowed.

Recommended Dosages

No dose has been established by a clinical trial. The only regulatory dose located is Health Canada's.

Dried herb (Health Canada oral monograph, January 30, 2026)

Adults 18 and older: 2 to 12 g of dried herb top per day, taken as dried or powdered herb or as a non-standardized extract (tincture, fluid extract, decoction, infusion or their concentrates), with dry extracts made only with ethanol, water or both. Products making the diuretic claim must say "For occasional use only."

Tinctures and glycerites

No independent dose exists. Health Canada's dose is expressed in grams of dried herb, so a liquid product can only be compared with it if the label states the herb-to-solvent ratio, which many do not.

Topical

Health Canada's topical monograph (2018) gives an example of a 1:1 fluid extract equivalent to 2 to 4 g of dried herb (2 to 4 mL), applied to minor cuts as needed. The trial lotion contained 1% extract.

Duration

No duration has been studied. The diuretic claim is licensed for occasional use only, and absent any long-term data, occasional, short-course use is the cautious reading. Historical and practitioner quantities from older herbals appear under Special Considerations and are not dosing guidance.

Timing & Administration

Ground ivy tea is traditionally taken after meals as a digestive bitter or between meals for coughs; no study tested either timing. Infuse dried herb in just-boiled water, covered, for about 10 minutes: the Croatian heat-assisted extraction reached its result in 10 minutes at 100 °C, and covering the cup keeps the small volatile fraction in. Do not swallow essential oil.

Timeline of Effects

There is no human timeline for oral use, because no oral trial was located.

Topical skin lightening

The lotion trial reported its result after 8 weeks; the abstract gives neither the application frequency nor any earlier read-out. Eight weeks is a reasonable minimum for any depigmenting product, since visible pigment fades slowly.

Rodent studies, for context only

The mouse gallstone study ran 3 weeks; the rat bile-flow measurement covered 2 hours after a single dose and found no significant change. These durations are not predictions for people.

When to conclude it is not working

For a digestive or cough tea, a fair personal trial is a few days for an acute complaint. A cough lasting more than 3 weeks, or any cough with blood, fever or weight loss, needs medical assessment rather than more tea.

Benefits of Taking Ground Ivy

The documented benefits are narrow:

• A placebo-controlled reduction in UV-induced pigmented spots from a 1% extract lotion over 8 weeks (Ha and colleagues, 2011), the only human efficacy result located.

• Traditional-use licensing in Canada for digestion, coughs and catarrh, diarrhea, hemorrhoids and minor wounds, which reflects a history of use, not proof of efficacy.

• Rosmarinic and chlorogenic acids from the tea, the same antioxidants supplied by rosemary, sage and lemon balm.

• Laboratory and rodent signals (liver protection after bile duct ligation, fewer gallstone crystals in mice, antibacterial activity against S. aureus) that justify a trial but do not substitute for one.

A cheap, palatable, bitter herbal tea with no documented serious human harm is a modest but real thing. Claims beyond that, including lead removal, kidney stone dissolution and tinnitus relief, are folklore.

Potential Negatives & Side Effects

Human reports on record

No published human adverse event case report for ground ivy was located. The lotion trial's abstract does not report adverse events. WebMD's monograph, without naming its source, rates the 1% lotion "possibly safe" for up to 8 weeks and says it "might cause stinging or itching in some people." There are no data on oral tolerance at any dose.

Diuretic and gastrointestinal effects

Health Canada's monograph treats a diuretic effect as an expected adverse reaction at 200 mg of dried herb per day or more. The French herbal reference Wikiphyto advises against prolonged use because of a risk of diarrhea. RxList states that larger amounts can irritate the stomach, intestines and kidneys and cause serious liver damage; it gives no amount and no source, and no measurement supports a threshold either way.

Cell toxicity, in the dish

The extracts are not inert. Sławińska and colleagues (Nutrients, 2023) found that a methanol extract and its fractions lowered the viability of human blood mononuclear cells to about 65% after 24 hours at 1 to 50 micrograms per mL, and one fraction caused DNA damage at 50 micrograms per mL. Grabowska's group found water and ethanol extracts of dried herb at 10 to 100 micrograms per mL non-toxic to normal human skin cells (HaCaT) and liver-derived HepG2 cells, while noting an earlier study in which a hot water extract of fresh plant cut HepG2 viability by about half at 100 micrograms per mL.

Deficiency Symptoms

What ground ivy addresses

No deficiency state exists. Ground ivy supplies no nutrient the body requires from it specifically; its potassium, calcium and fiber come in amounts per serving that ordinary vegetables exceed.

Bottom line

There is nothing to replete and no test that would show a need for it.

Toxicity Symptoms

At high intake

No human overdose, poisoning or organ injury attributed to ground ivy was located, in PubMed or in the regulatory documents reviewed. The toxicity record that does exist is veterinary, and the human warnings are borrowed from a different plant.

The horse record

The earliest source located is Harold Long's Plants Poisonous to Live Stock (Cambridge University Press, 1917), which included ground ivy, then Nepeta glechoma, only "as suspected of poisoning horses." The USDA plant guide, citing John Kingsbury's Poisonous Plants of the United States and Canada (1964), gives the description later sources repeat: after eating large amounts, especially of fresh plant or hay containing it, horses sweat, salivate, breathe with difficulty and show dilated pupils. It adds occasional pulmonary edema, and a University of Illinois toxic plant guide says such poisoning "is rarely fatal." Kingsbury is cited for the volatile oil as the likely cause; the bitter principle sometimes named, glechomin, has not been chemically characterized in any source located. The same guide (Pavek, 2013) cites a 2012 German paper by Vanselow and Brendieck-Worm in Zeitschrift für Ganzheitliche Tiermedizin for a threshold of "alfalfa hay containing 30% or more ground ivy" or a diet of ground ivy alone; that paper's German title asks whether ground ivy is the cause of fatal poisonings in horses, and its full text could not be retrieved. A 2023 Swiss equine series (Koch, Pferdewoche) says deaths are known but extremely rare. Across these sources no dated, located outbreak with a named number of animals was found, and a PubMed search returned no veterinary case report.

Cattle and other animals

The USDA guide states that no other livestock are known to be affected and that animals generally avoid the plant for its bitterness. The Forest Service review (Waggy, 2009) records that ground ivy "is thought to be toxic to livestock" and to some rodents, while wild boar and bank voles eat it. In a Czech rumen study (Komprda and colleagues, Archiv für Tierernährung, 1999), ground ivy had the highest phenolic acid content of 14 forage herbs tested, and 95.4% of its p-coumaric acid and 98.3% of its ferulic acid disappeared in the cattle rumen within 4 hours. No cattle poisoning report was located.

The pulegone question

Pulegone is the monoterpene ketone that makes pennyroyal oil (62% to 97% pulegone, per the European Medicines Agency) a liver poison: about 10 mL of the oil has caused moderate to severe toxicity in people and more than 15 mL has been fatal, with centrilobular liver necrosis. The claim that ground ivy contains pulegone rests on qualitative listings. The Australian Southern Cross University monograph cites a 1966 paper by Takemoto, Kusano and Hikino (Yakugaku Zasshi, volume 86) for menthone, pulegone and pinocamphone; Japan's Toyama traditional medicine database lists l-pulegone, l-menthone, isomenthone, l-pinocamphone and isopinocamphone for the Japanese plant without amounts; the USDA phytochemical database lists (+)-pulegone with no concentration. No percentage for pulegone in G. hederacea was located. The modern analyses tell a different story: Sile and colleagues identified 64 compounds and named β-myrcene, β-ocimene, germacrene D and B, 1,8-cineole and 1-octen-3-ol as the main ones; the 2024 Vietnamese oil's top five were p-sec-butylphenol (17.66%), 1,8-cineole (11.33%), germacrene D (9.97%), β-caryophyllene (9.19%) and γ-terpinene (7.12%).

Quantity matters more than presence. At the highest oil yield Sile's group measured (2.98 mL per kg), 12 g of dried herb, the top of Health Canada's daily range, holds about 36 microliters of total oil. The European Medicines Agency's 2016 public statement (EMA/HMPC/138386/2005 Rev. 1) accepts, for herbal medicinal products in the EU, a combined pulegone plus menthofuran intake of 0.75 mg per kg of body weight per day as a lifelong limit, 37.5 mg for a 50 kg adult (75 mg a day for use under one year). If that oil were pure pulegone (density about 0.94), it would weigh about 34 mg, within a few milligrams of the lifelong limit. Real oil is not pure pulegone, but because no one has measured how much it does contain, this worst case cannot be narrowed with data. The pennyroyal warning on labels is sound: it warns against adding a second, known pulegone source to one that is unmeasured.

Signs to reduce or stop

• Abdominal cramping, diarrhea or nausea.

• Markedly increased urination with dizziness or weakness, which suggests fluid loss.

• Stinging, itching or rash where a topical product was applied.

• Yellowing of the skin or eyes, dark urine or upper right abdominal pain, which require stopping and prompt medical review even though no ground ivy liver case has been located.

• In a horse: sweating, drooling, dilated pupils or labored breathing after grazing a ground ivy infested pasture or eating hay containing it, which needs a veterinarian.

General note

The one preparation with an open toxicity question is concentrated essential oil, which has no oral safety data and no reason to be swallowed. A further caution comes from one 2015 Lithuanian conference abstract (Stasiulionytė and colleagues), which reported estragole at 5.05% to 5.30% and methyl eugenol at 4.50% of the oil; both are rodent carcinogens, synthetic methyl eugenol was among the 7 flavorings the FDA delisted on October 5, 2018, and neither compound appears among the main constituents named in the peer-reviewed analyses above.

How Ground Ivy Works

Ground ivy's proposed actions come from several unrelated compound classes, and for none of them has a blood level been measured in a person after taking the herb.

Rosmarinic acid and the phenolic acids

Rosmarinic acid is an ester of caffeic acid that ground ivy shares with rosemary, sage and lemon balm. In isolated macrophages, ground ivy hot water extract lowered nitric oxide and malondialdehyde and reduced expression of the inflammatory genes iNOS, COX-2, TNF-alpha, IL-6 and IL-1β (Chou and colleagues, Life Sciences, 2019), and in the Latvian work pure rosmarinic acid at 100 micromolar cut the proportion of M1-type macrophages by 29%. Kim and colleagues (Bioorganic & Medicinal Chemistry Letters, 2011) found that three rosmarinic acid analogues from var. longituba inhibited NF-κB activation in liver cells. The rat liver and mouse gallstone results are usually attributed to this antioxidant and anti-inflammatory activity.

Ursolic and oleanolic acids

These pentacyclic triterpenes were isolated from ground ivy in 1986 by a Japanese group (Ohigashi and colleagues, Cancer Letters) as inhibitors of tumor-promoter-induced Epstein-Barr virus activation in cultured cells, and both inhibited skin tumor promotion in mice (Tokuda and colleagues, Cancer Letters, 1986). The Hitrechol study's authors point to ursolic acid's structural resemblance to ursodeoxycholic acid, the prescription gallstone-dissolving bile acid. Resemblance is not equivalence: the rat bile-flow study calculated that its Hitrechol dose delivered about 0.096 mg of ursolic acid per kg, against a lowest dose of 7.5 mg per kg in the earlier ursolic acid study it was compared with.

Flavonoids

Apigenin and luteolin from Japanese kakidoushi-cha strongly inhibited xanthine oxidase, the enzyme that makes uric acid; Masuda and colleagues (Journal of Nutritional Science and Vitaminology, 2013) estimated they accounted for about 35% of a methanol extract's inhibition and about 18% of a boiling-water extract's. No study located has measured uric acid in people drinking the tea. These two flavones occur mainly in flowering shoots.

A platelet-active fatty acid

Henry and colleagues (European Journal of Biochemistry, 1987) isolated 9-hydroxyoctadecadienoic acid (9-HODE) from a methanol extract of ground ivy and found that it raised adenylate cyclase activity in human platelet membranes about threefold, with half-maximal effect at 10 to 20 micromolar, acting as a partial agonist at prostaglandin receptors. Raised platelet cyclic AMP opposes platelet aggregation in principle. In human plasma, though, ground ivy extract and fractions at 1 to 50 micrograms per mL did not change prothrombin time, activated partial thromboplastin time or thrombin time (Sławińska and colleagues, 2023).

Gleheda, the leaf lectin

Ground ivy leaves make a carbohydrate-binding protein, Gleheda, related to legume lectins and specific for the Tn antigen (Wang and colleagues, Plant Physiology, 2003). In some wild clones it accounts for more than one third of total leaf protein; in others growing alongside it cannot be detected. It is a potent insecticide against Colorado potato beetle larvae and was not cytotoxic in the authors' tests. No study located has examined what it does when eaten by a mammal.

Bone cells

Hwang and colleagues showed that an ethanol extract first triggered and then desensitized dihydropyridine-sensitive voltage-gated calcium channels in mouse bone marrow macrophages, which blocked the calcium oscillations needed to form osteoclasts. That is a cell-culture mechanism with no animal or human follow-up.

Synergistic Supplements

No combination including ground ivy has been tested, and no specific traditional pairing was verified for this issue. Catnip is the closest relative covered in this archive. Because its main phenolic, rosmarinic acid, is shared with rosemary, sage and lemon balm, stacking several mint-family teas adds more of the same compounds rather than a new action. The one pairing to avoid is with pennyroyal or any concentrated mint-family essential oil, which adds monoterpene ketone exposure for no documented gain.

Interactions & What NOT to Take

No human drug interaction study and no interaction case report for ground ivy was located, and Health Canada's monograph requires no interaction statement. The cautions below are inferences, labeled as such.

Pennyroyal and pulegone-rich oils

The one interaction warning printed on labels is sound: do not combine it with pennyroyal herb or oil, whose pulegone is metabolized to the liver toxin menthofuran.

Diuretics and lithium

Health Canada treats a diuretic effect as an expected reaction. Anyone taking a prescription diuretic, or lithium, whose blood level rises when the body loses fluid and sodium, should not add a diuretic herb without their prescriber; the diuretic story itself belongs to another issue.

Anticoagulants and antiplatelet drugs

The platelet-active fatty acid 9-HODE gives a theoretical reason for caution with warfarin, apixaban, clopidogrel or aspirin, but the only plasma test found no change in clotting times at 1 to 50 micrograms per mL.

In human kidney cancer cells, a hot water extract and rosmarinic acid altered the response to cisplatin, in some assays protecting the cells against it (Chou and colleagues, Chinese Medicine, 2020); people on chemotherapy should clear any herb with their oncology team.

Quality, Testing & Adulteration

Species and name confusion

"Ivy" is the commonest mix-up: English ivy (Hedera helix) is a different plant in a different family, sold for coughs as ivy leaf extract. In Chinese commerce, ground ivy and its varieties have been sold as one of several regional "jinqiancao" herbs, whose pharmacopoeial species is Lysimachia christinae. East Asian research uses var. grandis and var. longituba, whose chemistry is not interchangeable with European G. hederacea. A label should give the Latin binomial and plant part.

Wild collection

Sile and colleagues reported in 2022 that European ground ivy is collected in the wild and that no commercial cultivated varieties exist. That means harvest site, not a farm specification, determines contamination. The Croatian samples were clean (arsenic, cadmium and lead below WHO limits of 1.0, 0.3 and 10 mg per kg), but they were collected by researchers from chosen sites; lawn and roadside collection is the scenario to worry about, given the plant's standing as a target of broadleaf herbicides such as 2,4-D and triclopyr.

Chemistry varies with harvest

In the Latvian trials, free apigenin and luteolin were found only in flowering shoots, rosmarinic and chlorogenic acids were higher in flowering shoots, and caffeic acid and essential oil peaked in vegetative growth. The Korean analysis of 22 regional hot water extracts of var. longituba (Hahm and colleagues, Plants, 2021) found rosmarinic acid consistently but polyphenol glucuronide ratios that varied dramatically. Two products both labeled "ground ivy herb" can differ severalfold in their main markers.

Third-party testing

No USP monograph, NSF listing or ConsumerLab review for ground ivy was located. The only official standard for European ground ivy located is the French Pharmacopoeia's homeopathic monograph, which sets a minimum for total hydroxycinnamic derivatives. Health Canada licenses products against its monograph's identity and dose terms and its general quality guide.

What to ask the seller for

A useful certificate of analysis for ground ivy names Glechoma hederacea and the aerial parts, confirms identity by microscopy or by thin layer chromatography against chlorogenic acid, caffeic acid and rutin, states harvest stage and whether the herb was wild-collected, reports lead, cadmium, arsenic and mercury against a stated limit, includes a pesticide and herbicide screen, and, for an extract, gives the solvent and herb-to-extract ratio. A rosmarinic acid figure is a bonus; no seller is required to give one.

Checks you can do yourself

Crushed dried ground ivy should smell distinctly aromatic and taste bitter. Whole or coarsely cut herb should show square stems and kidney-shaped, round-toothed leaves, often purplish beneath. A product labeled only "ivy," or one giving a Hedera name, is not this herb. A liquid without a ratio cannot be compared with Health Canada's gram-based dose at all.

Special Considerations

Alehoof: the brewing history

The name alehoof records ground ivy's use in ale. Salmon's Botanologia (1710) said that put into ale while it was working, it was "said to clarify and make fine the Drink in about 24 hours time." Woodville's Medical Botany (1790 to 1794) noted that Ray and Mead spoke of its being joined with fermenting ale, and Grieve's A Modern Herbal (1931) described it as a clarifying and flavoring agent displaced by hops. Brewing history is not evidence of a health effect; it explains why the plant was everywhere.

Historical quantities, in context only

King's American Dispensatory (1898) gave half a drachm to 1 drachm of powdered leaves (roughly 2 to 4 g), 1 to 2 fluid ounces of infusion, and 1 to 15 drops of a tincture of the fresh plant in 98% alcohol. Salmon gave the juice at 1 to 4 ounces "according to Age and Strength." These describe 18th and 19th century practice, not guidance; Health Canada's figures under Recommended Dosages are the only current ones.

Regulatory status

In the United States ground ivy is sold as a dietary supplement ingredient with no FDA review of safety or efficacy. In Canada it is licensed under the 2026 oral and 2018 topical monographs. Ground ivy does not appear in the European Medicines Agency's inventory of herbal substances for assessment (May 2021 update), so there is no EU herbal monograph. Connecticut bans its distribution as an invasive plant, according to the Forest Service review.

Pulegone in the wider regulatory record

Because labels raise pulegone, its status matters: the US National Toxicology Program (Technical Report 563, August 2011) dosed rats and mice by gavage at 18.75 to 150 mg per kg for 2 years and found clear evidence of urinary bladder tumors in female rats at the top dose and liver tumors in mice at 37.5 to 150 mg per kg; IARC classifies it as possibly carcinogenic to humans (Group 2B); California listed it under Proposition 65 effective April 18, 2014; and the FDA removed synthetic pulegone from its permitted flavoring list on October 5, 2018, without changing the status of foods containing it naturally. These actions concern pulegone at measured doses, not ground ivy.

Research Status & Evidence Quality

A PubMed search on November 2, 2026 for ground ivy or Glechoma in titles and abstracts combined with patients, volunteers, subjects or randomized returned 3 records: the Ha lotion trial, a rat study, and a lectin microarray study of blood antibodies that did not test the herb.

Tier 1, chemistry (strongest)

Phenolic acids, flavonoids, triterpenes and essential oil have been quantified by HPLC, LC-MS and GC-MS in Latvian, Croatian, Polish, Romanian, Korean and Vietnamese material. The weakness is the oil: modern analyses disagree with one another by origin, and the pulegone attribution has no measured figure behind it.

Tier 2, one topical human trial

Ha and colleagues (2011): randomized, double-blind, placebo-controlled, 8 weeks, 1% lotion, female Asian volunteers, cosmetic endpoint. Sample size not available in the abstract. No oral trial was located.

Tier 3, rodent studies

Bile duct ligation in rats (Wang, 2017) and a 3-week gallstone model in mice with 4 to 6 animals per group (Xiao, 2021). Neither tested a tea at a human-equivalent intake, and the gallstone study was conducted with a manufacturer-supplied product.

Tier 4, cell and dish studies

Anti-inflammatory, antioxidant, anti-melanogenic, osteoclast and antimicrobial results, mostly at 1 to 750 micrograms per mL, concentrations not shown to be reached in blood.

Tier 5, tradition and veterinary textbooks

Lead colic, tinnitus, alehoof and the horse warnings rest on herbals from 1597 to 1931 and on Long (1917) and Kingsbury (1964).

Research Limitations

No pharmacokinetic data for any ground ivy constituent in people were located. No oral trial for any indication was located. No measured pulegone content was located. No documented horse outbreak with dates and numbers. Species and variety differ across the East Asian and European literature, and the Gleheda lectin varies from absent to over a third of leaf protein between clones, so even "the same herb" is chemically inconsistent. A 2026 review in Planta Medica (Krasocka and colleagues) concluded that animal experiments and clinical studies are still needed.

Summary & Key Takeaways

Bottom Line

Ground ivy is a common mint-family weed with a rich folk record, well-characterized phenolic chemistry and essentially no human evidence: one 8-week cosmetic trial of a 1% lotion, and nothing for the teas, tinctures and capsules on sale. Its three famous warnings and claims all rest on thin records, which leaves the warnings unresolved rather than disproven. The horse poisoning rests on textbook descriptions with no outbreak record located, the pulegone is a qualitative listing without a measured amount, and the lead colic cure is dispensatory testimony that no study located has tested.

Key Safety Points

• Pregnant or nursing women and children should not take it.

• Avoid with kidney or liver disease, and check with a prescriber first if you take a diuretic, lithium or an anticoagulant.

• Never combine it with pennyroyal or swallow any mint-family essential oil, including ground ivy oil.

• Choose products that name Glechoma hederacea and the aerial parts, and avoid lawn or roadside foraging.

• Keep horses off pastures and hay heavily infested with it.

• Lead exposure needs a blood lead test, not an herbal tea.

Special Note

The honest label for ground ivy is "untested," which is different from both "proven" and "dangerous." Sellers who print the pulegone warning should be able to say how much pulegone their herb contains, and those who sell it for lead or heavy metals should be able to name one measurement. On the evidence located for this issue, neither has been published.

Forwarded this, or reading it on the web? to get the next breakdown.

Researched and drafted with AI assistance. Every claim verified against primary sources and human-reviewed before publication. Last reviewed: November 2, 2026. Corrections: reply to any issue.

This issue is educational and is not medical advice. If you take any prescription medicine, especially a diuretic, lithium or a blood thinner, have kidney or liver disease or another diagnosed condition, or are pregnant or breastfeeding, talk to a clinician before taking ground ivy or changing anything.