Houttuynia

What is Houttuynia?

Houttuynia cordata is eaten as a vegetable across East and Southeast Asia, and the 2020 Chinese Pharmacopoeia doses the dried herb at 15 to 25 g. It is a low, creeping perennial of the lizard's-tail family (Saururaceae), the only species in its genus, and a crushed leaf gives off the smell behind its Chinese name, yu xing cao, "fish-smell herb." It grows in damp, shaded ground from Japan and Korea through China, Taiwan and Southeast Asia into northeast India.

The same plant reaches people in three very different forms. In southwest China the rhizome is sold as zhe'ergen ("folding-ear root") and eaten as a vegetable; a 2022 metabolomics paper from Chinese researchers (Qi and colleagues, Molecules) notes that in China "people only consume its roots and discard the stems and leaves." In Vietnam the leaves, called diếp cá, are eaten fresh as a herb. In Japan the flowering aerial parts are dried as dokudami, and one registered product, Tochimoto Jūyaku P, is a Class 3 over-the-counter laxative listed by Japan's Pharmaceuticals and Medical Devices Agency.

Chinese medicine classes the herb as heat-clearing and detoxifying. The 2020 Pharmacopoeia lists it for phlegm-heat cough, lung abscess, dysentery, painful urination and skin abscesses, and directs that the decoction not be boiled for long, because the aromatic oil is volatile. Chinese manufacturers also turned the herb into injectable products given by intramuscular shot and intravenous drip; a 2009 Beijing Review report counted more than 100 factories making Yuxingcao injection. That route is where the plant's serious safety record comes from.

In North America and Europe, Houttuynia is sold mainly as alcohol tinctures and capsules marketed for "immune" or "microbial" support. Much of that demand traces to the herbalist Stephen Harrod Buhner, whose 2013 book Healing Lyme Disease Coinfections (Healing Arts Press) names houttuynia, alongside cordyceps, as one of the best herbal examples for mycoplasma infection.

Common Names

• Fish mint, fishwort, heartleaf houttuynia, chameleon plant (the variegated garden form)

• Yu xing cao (China), zhe'ergen for the edible rhizome (southwest China)

• Dokudami, and jūyaku for the dried drug (Japan)

• Diếp cá (Vietnam), eoseongcho (Korea)

• Houttuyniae Herba (pharmacopoeial name)

Primary Active Compounds

• Volatile oil: 0.06% to 0.14% of aerial parts and 0.08% to 0.16% of underground stem in Indian samples analyzed by Verma and colleagues (2017, Chemistry & Biodiversity). The main constituent was 2-undecanone (methyl nonyl ketone), at 19.4% to 56.3% of aerial-part oil and 29.5% to 42.3% of underground-stem oil, followed by myrcene.

• Houttuynin (decanoyl acetaldehyde): a reactive beta-keto aldehyde, unstable and readily converted to 2-undecanone, that is the parent compound of the injection chemistry.

• Sodium houttuyfonate and sodium new houttuyfonate: water-soluble salts. Sodium houttuyfonate is made by reacting houttuynin with sodium bisulfite, and sodium new houttuyfonate is a closely related synthetic analog. They are made in a factory, not found in the plant.

• Flavonoids: quercitrin, isoquercitrin, rutin and hyperoside, around 0.1% of the herb by one 2024 review's estimate.

• Polysaccharides, chlorogenic acid and a family of alkaloids that includes aristolactams (aristolactam AII, FI and BII), the compounds behind the plant's kidney-safety debate.

Key Note

Three products share one name: a vegetable, a dried or extracted herb taken by mouth, and an injectable drug. Evidence about one does not transfer to the others, and most of what is alarming about Houttuynia belongs to the third.

What follows covers the herb a Western buyer can actually purchase, and the injection history that buyer should know about.

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Primary Functions & Benefits

The marketed functions of Houttuynia fall into four groups: respiratory and sinus complaints, allergy, antimicrobial or antiviral activity, and gut inflammation. The human evidence for each is thin, and almost all of it tests the herb inside a multi-herb formula.

Chronic sinusitis

This is the best-tested oral use, and the results are mixed. In a Taiwanese trial from Taichung Veterans General Hospital (Liang and colleagues, 2011, American Journal of Rhinology & Allergy), patients recovering from functional endoscopic sinus surgery were randomized to Tsang-Erh-San extract granules plus Houttuynia extract powder for 8 weeks, amoxicillin for 4 weeks, or placebo. Of the 97 who completed the study (33, 34 and 30 per arm), the herbal group improved on symptom scores, endoscopy and acoustic rhinometry, but so did the other two groups, and the authors found "no significant differences in subjective and objective treatment outcomes among three groups." A follow-up trial from the same hospital (Jiang and colleagues, 2012) compared the same herbal combination with erythromycin for 8 weeks in chronic sinusitis without polyps. Among 53 completers (26 herbal, 27 erythromycin), 20-item Sino-Nasal Outcome Test scores fell in both groups with no significant difference between them, and the authors wrote that "a placebo effect remained possible in both treatment groups."

Allergic rhinitis

A 2022 open-label trial in Taiwan (Chang and colleagues, Journal of the Chinese Medical Association) enrolled 45 adults with perennial allergic rhinitis and analyzed the 42 who completed it, 21 per arm, after randomization to an 11-herb tea called Zheng-Yi-Fang or to their usual Western medication for 4 weeks. Houttuynia made up 20% of each 4 g tea bag, or 0.8 g. Nasal symptom scores on the Chinese Rhinosinusitis Outcome Measures fell by 23.1 points in the tea group against 4.2 in the control group. The outcome assessor was blinded, but the participants were not, and the control group simply continued what they were already taking.

Ulcerative colitis

A 2004 report in the World Journal of Gastroenterology (Jiang and Cui) randomized 42 people with a first episode of ulcerative colitis to "Heartleaf houttuynia herb" or sulfasalazine, 21 per arm. Complete remission was reported in 20 of 21 (95.2%) on the herb versus 15 in the sulfasalazine group, with stool frequency normalizing in 5.6 days versus 9.5. The abstract does not specify the preparation, dose or route, it describes no blinding, and I found no later replication.

Acne

A Seoul National University trial (Yang and colleagues, 2019, Journal of Dermatological Treatment) randomized 60 patients with mild to moderate acne 1:1 to a blinded herbal extract cleanser applied to the skin, combining Houttuynia with mangosteen and other herbs, or a vehicle cleanser, for 8 weeks. Inflammatory and non-inflammatory lesion counts fell significantly in the herbal group. This was a topical product, not an oral one, and the design cannot attribute any of the effect to Houttuynia.

Antiviral and antimicrobial activity

The antiviral case for Houttuynia itself is laboratory work. Chiow and colleagues (2015, Asian Pacific Journal of Tropical Medicine) found that an ethyl acetate fraction of the herb blocked a mouse coronavirus at an IC50 of 0.98 micrograms per milliliter and dengue virus type 2 at 7.50 micrograms per milliliter in cell culture. The anti-biofilm and anti-quorum-sensing studies use sodium houttuyfonate or sodium new houttuyfonate against bacteria and fungi in culture; I found no study measuring whether such concentrations reach human tissue after an oral dose. Some Chinese patent medicines list Houttuynia among many herbs and have been tested against placebo: in one double-blind trial of Lianhua Qingwen granules, a 13-herb formula, 174 adults with non-influenza viral pneumonia were randomized, and symptom relief at 7 days averaged 82.98% versus 75.11% on placebo in the 151-patient analysis set (Ma and colleagues, 2024, Frontiers in Medicine). Houttuynia's share of that effect cannot be separated.

Lyme disease

Lyme protocols are where most Western buyers meet this herb, and they rest on herbalist recommendation rather than trial data. A title and abstract search of PubMed pairing Houttuynia with Borrelia, Lyme or biofilm returned eight papers, none of them a human study and none testing Borrelia.

Forms & Standardization

No Houttuynia supplement sold in the US is standardized to a marker compound, and no marker has been agreed. A 2024 review in Current Issues in Molecular Biology (Yang and colleagues) proposed 2-undecanone, sodium houttuyfonate, quercetin and quercitrin as candidate quality markers, which tells you the field is still choosing what to measure. The forms differ enough that the choice matters more than the brand.

Dried herb (Houttuyniae Herba)

The Chinese Pharmacopoeia material is the fresh whole plant or the dried aerial parts. The Japanese drug jūyaku is the aerial parts collected at flowering. Drying and boiling drive off much of the volatile oil, which is why Chinese practice adds the herb late to a decoction; a 2024 review put the oil at roughly 0.05% of the plant, and houttuynin itself converts toward 2-undecanone during processing.

Water extracts and teas

Hot-water preparations carry the flavonoids, polysaccharides and some of the volatile fraction. They also appear to leave the aristolactams behind: Xu and colleagues (2023, Journal of Pharmaceutical and Biomedical Analysis) quantified three aristolactams in 30 batches from different regions and plant parts and detected none in the water extract of any part. The tea bag in the Taiwanese rhinitis trial was a water-steeped formula containing 0.8 g of Houttuynia per 4 g bag.

Extract powders and granules

The Taiwanese sinus trials used Houttuynia extract powder, manufactured as a concentrated granule product, combined with Tsang-Erh-San. The papers do not report a marker content or a herb-to-extract ratio for the Houttuynia component.

Alcohol tinctures

These dominate the Western market and are the form least represented in research. NutraMedix Houttuynia, a 30 ml tincture sold for "immune/microbial support," lists one ingredient, "Houttuynia herb extract," at 1.5 ml per 30-drop serving, in mineral water and 20% to 24% ethanol, with 20 servings per bottle. The label gives no plant part, no herb-to-solvent ratio and no marker content, so a buyer cannot convert a serving into grams of herb. Aristolactams were undetectable in water extracts in the Xu study, but analysts pull them out of the plant with methanol, so an alcohol extract is the form more likely to carry them; I found no published measurement of aristolactams in a commercial tincture. The rat toxicity study discussed in Section 14 used a 95% ethanol extract.

Capsules

Capsules contain either powdered dried herb or a dried extract. Without a declared ratio, a 500 mg capsule of powder and a 500 mg capsule of a 10:1 extract differ by about tenfold in herb equivalent.

Sodium houttuyfonate and sodium new houttuyfonate

These semi-synthetic salts were developed because houttuynin is too unstable to formulate. A 1997 veterinary trial (Hu and Du, Journal of Veterinary Medicine Series B) infused 80 mg of the houttuynin sodium salt into the udder against bovine mastitis in 104 cases, with cure rates similar to penicillin plus streptomycin. Nearly all of the "biofilm" and anti-quorum-sensing literature uses these salts, not the herb.

Injections (history and current status)

Houttuynia injection and its relatives were given by intramuscular shot and by intravenous drip. The family included sodium new houttuyfonate injections, Yujin injection (Houttuynia with honeysuckle) and Compound Dandelion injection (dandelion, Houttuynia and wild chrysanthemum). The 2006 regulatory sequence ran as follows:

• June 1, 2006: the State Food and Drug Administration suspended use and approval of Houttuynia injection and six other injectables.

• September 5, 2006: notice 国食药监办[2006]461号 set out decisions on the seven injections.

• September 15, 2006: notice 国食药监办[2006]474号 set the application procedure for resuming intramuscular Houttuynia and sodium new houttuyfonate injections.

• November 3, 2006: notice 国食药监注[2006]561号 issued a revised intramuscular-only label carrying the warning "本品可能导致严重过敏反应！" ("This product may cause serious allergic reactions!"), listing anaphylactic shock and laryngeal edema among its reactions, and contraindicating it in anyone allergic to the product and in pregnant women and children.

• March 14, 2007: notice 国食药监注[2007]133号 revised the labels of Yujin and Compound Dandelion injections as intramuscular products, contraindicating them in anyone with a history of allergy or serious reaction to Houttuynia-type products, and contraindicating Compound Dandelion injection in pregnant women and children because of its benzyl alcohol excipient.

The resumption documents describe intramuscular products only. In 2025 China's National Medical Products Administration, National Health Commission and National Administration of Traditional Chinese Medicine circulated a draft notice on post-market evaluation of traditional Chinese medicine injections (September 19), and the agency's Center for Drug Evaluation published technical requirements for that re-evaluation on October 17, according to Caixin.

Food Sources

Houttuynia is itself the food. It is one of the few herbs on the US supplement shelf that is also sold as an ordinary vegetable in Asian markets, and China lists yu xing cao among the substances it classes as both food and medicine.

Which part, where

• Rhizome (zhe'ergen): the main edible part in southwest China.

• Leaves and young shoots: eaten fresh in Vietnam and parts of northeast India.

• Dried aerial parts: brewed as dokudami tea in Japan.

What the edible parts contain

Composition data per serving are scarce. Qi and colleagues (2022) ranked parts rather than reporting absolute values: vitamin C was highest in the roots, while total flavonoids, soluble sugars and protein were highest in the leaves. The aroma comes from a volatile oil that makes up well under 1% of fresh weight.

The plant part also changes the aristolactam load. In the 30 batches Xu and colleagues analyzed, aerial parts contained 3.20 to 108.19 micrograms of the three aristolactams per gram, underground parts 0.95 to 11.66 micrograms per gram, and flowers had the highest content. The rhizome that southwest China eats is, by that measure, the lower-exposure part, and the flowering tops that Japan dries for tea are the higher one.

How cooking changes it

Heat drives off the volatile oil, so a cooked or long-boiled preparation carries less 2-undecanone than a raw one. Water extraction appears to leave the aristolactams in the plant material, which is consistent with the long culinary record but does not cover alcohol extracts.

Is dietary intake enough?

For culinary purposes, yes; for the antimicrobial claims made about supplements, nobody has established a target intake from either food or pills. Fudan University researchers who fed purified Houttuynia aristolactams to mice (Xue and colleagues, 2025, Food Research International) concluded their data supported "the safe consumption of H. cordata at typical dietary levels" while calling for aristolactam monitoring in edible herbs.

Who Should Take Houttuynia

Nobody needs Houttuynia, and no medical condition has trial evidence strong enough to recommend it. Reasonable candidates are narrower than the marketing suggests.

• People who already eat it as a vegetable, for whom a modest culinary amount is a long-standing dietary habit rather than a supplement decision.

• Adults trying a traditional preparation for nasal or sinus congestion, with the understanding that a placebo-controlled trial found no advantage over placebo after sinus surgery, and the positive rhinitis trial was open-label and used an 11-herb blend.

• Adults in Japan using a registered jūyaku product for occasional constipation according to its approved label.

People with Lyme disease, Bartonella or Mycoplasma infection should not treat Houttuynia as a substitute for antibiotics. No human data support it for those infections, and a delayed effective treatment is a real cost.

Who Should AVOID or Use Caution

Contraindications

• Anyone who has reacted to a Houttuynia injection or sodium houttuyfonate product. China's November 2006 label for intramuscular Houttuynia injection contraindicated it in anyone allergic to the product, and the March 2007 labels for two other Houttuynia-containing injections contraindicated them in people with a history of allergy or serious reaction to Houttuynia-type products. Cross-reactivity between the injected and oral forms has not been studied, so a prior reaction is a reason to avoid the herb entirely.

• Pregnancy and breastfeeding. There are no human safety data. A 2023 study in Toxins (Liu and colleagues) concluded that Houttuynia "may affect embryonic development," based on zebrafish embryos, cultured embryoid bodies and network modeling, China's November 2006 label for intramuscular Houttuynia injection contraindicated it in pregnant women, the NutraMedix tincture label says "Do not use if pregnant or nursing," and the Japanese jūyaku label tells pregnant women to consult a doctor or pharmacist first.

• Kidney disease. The plant's aristolactams are structural relatives of aristolochic acid and were toxic to human kidney tubule cells in culture. Food-level exposure looks low, but someone with reduced kidney function has no margin to test a concentrated extract on.

Use Caution

• People with drug allergies. In the 2010 systematic review of injection reactions, 286 of the 1,232 cases had a detailed allergy history recorded, and penicillin allergy accounted for 15.03% of those.

• Children. In a 2011 analysis of injection adverse events tied to inappropriate use (Cui and colleagues), 294 cases arose in papers concerning contraindications, and 290 of them were children; China's November 2006 intramuscular label contraindicated the injection in children. That record concerns injections, but no pediatric dose of any oral form has been tested.

• Liver disease. Repeated high doses of a 95% ethanol extract damaged rat livers as well as kidneys (Section 14).

• People taking other laxatives. The Japanese jūyaku label, approved as a laxative, says not to combine it with other laxatives.

Critical Safety Point

Houttuynia should never be injected, and no oral product should be given by any other route. The 2011 analysis by Cui and colleagues found 16 unauthorized ways of using Houttuynia injection in the literature, seven of which produced adverse events, including injection into body cavities (20 cases), aerosol inhalation (13), rinses (10) and drinking the injection solution (8).

Recommended Dosages

No clinical trial has established an effective dose of Houttuynia taken alone for any condition. The figures below are what pharmacopoeias and approved or commercial labels state, and none of them applies to Lyme disease, viral infection or biofilm claims.

Dried herb, decoction (Chinese Pharmacopoeia, 2020)

15 to 25 g of dried herb, decocted only briefly so the volatile oil is not boiled off. A Taiwan Ministry of Agriculture reference page states that fresh herb used as juice is taken at double that amount.

Dried aerial parts, decoction (Japanese OTC label)

Tochimoto Jūyaku P directs adults 15 and older to boil 12 g in about 600 ml of water down to about 400 ml, strain it, and drink it in three portions over the day. This is an approved laxative indication for constipation, reduced urine output and constipation-related skin eruptions, not a general wellness dose.

Alcohol tincture (commercial label)

The NutraMedix label starts at 1 drop and works up to 30 drops (1.5 ml) two to four times daily. Because the label declares no herb equivalent, there is no way to compare that amount with the pharmacopoeia range.

Tea formula (trial preparation)

The Zheng-Yi-Fang rhinitis trial gave 0.8 g of Houttuynia per 4 g tea bag inside an 11-herb blend for 4 weeks. That is a formula dose, not a Houttuynia dose.

Capsules and extract powders

No label standard exists. Without a declared extract ratio and plant part, convert nothing and assume nothing.

Duration

The Japanese label says to stop and consult a professional if symptoms have not improved after 5 to 6 days when taken for constipation or constipation-related skin eruptions, or after about one month otherwise. Human trials of Houttuynia-containing formulas ran 4 to 8 weeks. None of the human trials I found followed oral use beyond 8 weeks, so open-ended daily use is untested territory.

Timing & Administration

• Brew briefly. The volatile fraction is lost to long boiling, which is why Chinese practice adds the herb near the end of a decoction.

• Before or between meals. The Japanese label specifies dosing before meals or between meals; the NutraMedix label specifies 30 minutes before meals, diluted in 4 oz (120 ml) of water.

• Expect the smell. Fresh leaf and tincture taste distinctly fishy. That is the 2-undecanone and related ketones, not spoilage.

• Start low with tinctures, as the NutraMedix label itself directs, because the fastest reactions to the injected form began within one minute and I found no study characterizing oral sensitivity.

• Keep the route oral. Houttuynia products are not for nasal sprays, eye use or injection unless a product is specifically approved for that route.

Timeline of Effects

Onset

In the Taiwanese rhinitis trial, the 23.1-point drop in nasal symptom scores was measured at the 4-week endpoint; no earlier time point was reported. In the 2004 ulcerative colitis report, stool frequency normalized in a mean of 5.6 days, blood in the stool disappeared in 6.7 days and abdominal pain resolved in 6.1 days on the herb.

Peak effect

The sinus trials assessed outcomes at 8 weeks, with CT scans at 12 weeks after surgery. Symptom scores improved over that span in every arm, including placebo, so the timeline of the herb's own effect cannot be separated from natural recovery.

A fair trial

Four weeks for nasal symptoms matches the only positive rhinitis trial. For constipation, the approved Japanese label sets the limit at 5 to 6 days.

When to conclude it is not working

If nasal symptoms have not changed by 4 weeks, the trials offer no reason to expect a late response. For any infection, including Lyme disease, the absence of human data means there is no timeline to wait for.

Benefits of Taking Houttuynia

Every human benefit below comes from a small trial, most of them multi-herb formulas, and I found no independent replication of any of them.

• Nasal symptoms in allergic rhinitis: a 23.1-point fall in nasal symptom scores versus 4.2 on usual care after 4 weeks of an 11-herb tea containing 20% Houttuynia (42 completers, open-label, Taiwan, 2022). No side effects were reported.

• Chronic sinusitis: symptom scores improved as much on Tsang-Erh-San plus Houttuynia extract as on erythromycin over 8 weeks (53 completers, 2012), and no better than placebo after sinus surgery (97 completers, 2011).

• First-episode ulcerative colitis: 20 of 21 in complete remission on the herb versus 15 of 21 on sulfasalazine (2004, preparation unspecified, single center).

• Acne: fewer inflammatory and non-inflammatory lesions after 8 weeks of a multi-herb extract cleanser applied to the skin (60 patients, 2019); Houttuynia's share of the effect is unknown.

• Sinus irrigation after surgery: a 2001 Chengdu study of 192 patients reported better results with a Herba Houttuyniae irrigation fluid than with two comparison fluids. That was a topical rinse, not an oral product.

Animal and cell studies add claims that have not reached people: oral water extract blocked mast-cell anaphylaxis in mice (Li and colleagues, 2005, Biological & Pharmaceutical Bulletin; Han and colleagues, 2009, Food and Chemical Toxicology), 2-undecanone at 100 to 400 mg/kg given by stomach tube reduced airway inflammation in asthmatic mice (Song and colleagues, 2022), and Houttuynia polysaccharides eased atopic-dermatitis-like lesions in mice (Huang and colleagues, 2025).

Potential Negatives & Side Effects

Oral use

The oral side-effect record is sparse rather than clean. The 2022 rhinitis trial reported no side effects in 21 tea drinkers over 4 weeks; the 2019 acne trial, which reported no serious adverse events, used a cleanser on the skin and says nothing about oral use. In the larger Lianhua Qingwen pneumonia trial, adverse reactions were reported in 4.60% of the 13-herb formula group and 2.44% on placebo, a difference that was not significant, but that formula cannot isolate this herb. The Houttuynia-focused samples are too small to rule out a reaction affecting several percent of users. Expected nuisance effects are a strong fishy taste and, with a laxative-strength decoction, loose stools; the Japanese label tells users to stop if diarrhea persists or worsens.

Injected use

The injection record is large and serious. Across 1,232 published cases reviewed by Wang and colleagues at Sichuan University's West China Hospital (2010, Journal of Evidence-Based Medicine), reactions involved the respiratory system in 37.42% of cases, skin in 34.66%, the digestive system in 25.49%, the circulatory system in 25.41% and the nervous system in 23.96%. Graded by WHO criteria, 22.56% were the most serious grade, and anaphylactic shock made up 58.99% of those. All deaths but one were from allergic shock; the exception was multiple organ failure after anaphylactic purpura. The fastest three reactions began one minute after injection.

A retrospective analysis of China's spontaneous reporting database for 2006 to 2008, published in Herald of Medicine in 2016, counted 2,282 reports for Yuxingcao preparations. Of these, 98.07% involved intravenous use, 308 (13.50%) were serious, 191 (8.37%) were allergic shock, and 22 patients died. Expiratory dyspnea, at 27.25%, was the commonest symptom.

Kidney and liver questions

These come from laboratory and animal data on the plant's aristolactams and on high-dose ethanol extracts, covered in Sections 14 and 18. They are reasons for caution with concentrated extracts, not documented harms from eating the plant.

Deficiency Symptoms

There is no Houttuynia deficiency, and none of its compounds is required by the human body.

What Houttuynia addresses

Nothing that the body lacks. The herb is used for symptoms, mainly respiratory congestion, constipation and skin complaints in its traditional systems. A genuine nutrient such as vitamin C has a defined deficiency disease, scurvy, and a measurable blood level; Houttuynia has neither, which is why no laboratory test can tell you whether you "need" it.

Bottom line

Skipping Houttuynia causes no deficiency state. Any decision to take it should rest on the condition being treated and the strength of the trial evidence for that condition.

Toxicity Symptoms

At high intake

The clearest oral toxicity data come from rats. Chen and colleagues (2021, Journal of Applied Toxicology) gave Sprague-Dawley rats a 95% ethanol extract. A single 2,000 mg/kg dose produced no deaths, and 250 mg/kg daily for 28 days produced no significant adverse effect. At 500 and 1,000 mg/kg daily, five rats died and the animals showed liver and kidney toxicity, with males more susceptible than females. A 2021 Chinese safety review (Lyu and colleagues, Chinese Traditional and Herbal Drugs) cites a 13-week rat study of an ethanol extract with a no-observed-adverse-effect level of 999 mg/kg daily in males and 350 mg/kg daily in females. In mice, Fudan University researchers found that Houttuynia aristolactams given orally for a subacute period produced only "modest elevations" in kidney markers, far less than aristolochic acid I, because oral bioavailability was 52.71% for aristolactam I and 39.60% for aristolactam BII against 99.83% for aristolochic acid I. These are animal figures and do not translate into a safe human amount.

Signs to reduce or stop

• Hives, flushing, itching, wheezing, chest tightness or lip and throat swelling after a dose: stop and seek urgent care for any breathing difficulty.

• Persistent or worsening diarrhea or abdominal pain.

• Reduced urine output, swelling of the ankles, or unusual fatigue during long-term use of a concentrated extract.

• Yellowing of the skin or eyes, or dark urine.

General note

Food-level eating has a long record without a documented toxicity syndrome. The hazard rises with concentration, ethanol extraction, aerial parts and flowers, long daily use, and above all with injection.

How Houttuynia Works

The proposed mechanisms split cleanly by route, and the injected and oral stories point in opposite directions: the injection triggered mast cells, while oral extracts in animals calm them.

Why the injection caused anaphylaxis

Three explanations have been tested, and they are not mutually exclusive.

• Houttuynin binds human proteins. Deng and colleagues at the Shanghai Institute of Materia Medica (2012, Biomedical Chromatography) showed that houttuynin, a beta-keto aldehyde, forms Schiff-base adducts with lysine residues on human serum albumin, specifically Lys-212, Lys-414 and Lys-525, plus pyridinium adducts at Lys-414 and Lys-432, and binds the N-terminal valine of hemoglobin chains. Protein adducts like these can act as new antigens, a plausible route to true allergy.

• Direct mast-cell activation through MRGPRX2. Sun and colleagues (2022, Journal of Ethnopharmacology) found that mice lacking Mrgprb2, the mouse version of the human receptor MRGPRX2, had significantly less mast-cell degranulation, histamine release and paw swelling after Houttuynia injection. That points to a non-antibody "anaphylactoid" mechanism that needs no prior sensitization.

• The solubilizer. Some Houttuynia injections contained polysorbate 80 to keep the oil in solution, and Chinese researchers proposed the excipient as a cause of the reactions. A beagle study in 2011 (Sun and colleagues, Chinese Journal of Integrated Traditional and Western Medicine) found no typical anaphylactoid reaction from the injection at 0.25% or 0.30% polysorbate 80, so the excipient theory remains unsettled.

The intravenous route bypasses the gut, where digestion would break down large molecular complexes, and puts the whole dose into the bloodstream at once. Chinese researchers (He and colleagues, 2016, China Journal of Chinese Materia Medica) argued on these grounds that oral use should be far less immunogenic than injection, which is consistent with the 6.86-fold higher reaction odds for intravenous versus intramuscular use.

What oral extracts do in animals

• Mast-cell stabilization: oral water extract inhibited compound 48/80-induced systemic anaphylaxis in mice and blocked histamine release from rat mast cells (Li and colleagues, 2005), and suppressed phosphorylation of Syk, Lyn, LAT, Gab2 and PLC gamma 2 in IgE-stimulated cells (Han and colleagues, 2009).

• NF-kappa B inhibition: 2-undecanone reduced IL-4, IL-5, IL-13 and IgE in the airways of ovalbumin-challenged mice (Song and colleagues, 2022).

• Airway calcium signaling: Houttuynia essential oil lowered inositol trisphosphate receptor expression in human bronchial smooth muscle cells and in house dust mite-sensitized mice (Huang and colleagues, 2023, Biomedicine & Pharmacotherapy).

• Antiviral activity in culture: the ethyl acetate fraction interfered with mouse coronavirus and dengue infection of cells (Chiow and colleagues, 2015).

None of these has been confirmed by a measured effect in a human given an oral dose.

Synergistic Supplements

No combination involving Houttuynia has been tested against Houttuynia alone, so "synergy" here describes how the herb is traditionally combined, not a demonstrated effect.

• Tsang-Erh-San: the Xanthium-based classical formula paired with Houttuynia extract in both Taiwanese sinusitis trials. The pairing matched erythromycin in one trial and did not beat placebo in the other.

• Platycodon (jie geng) and Scutellaria (huang qin): the second and third largest components of the Zheng-Yi-Fang rhinitis tea, at 16.5% and 14% of each bag.

• Honeysuckle: combined with Houttuynia in the Yujin injection, an intramuscular product, so the pairing has no oral trial behind it.

• Cordyceps: named alongside houttuynia in Buhner's Lyme coinfection protocols. Other herbs in those protocols, such as Cat's Claw, are covered in their own issues of this archive, and none of the combinations has been tested in a published trial that I found.

Interactions & What NOT to Take

Antibiotics (injection data)

In the 2010 systematic review, Houttuynia injection given together with a macrolide antibiotic carried a relative risk of adverse reaction of 8.80 (95% CI 6.12 to 12.65) compared with the injection alone, and the injection was commonly co-administered with cephalosporins and penicillins. These are injection findings. I found no study of oral Houttuynia with erythromycin, azithromycin or clarithromycin, but a Lyme patient on doxycycline or azithromycin who adds a tincture is combining products with no interaction data at all.

Acetaminophen and CYP2E1

Taiwanese researchers (Chen and colleagues, 2014, BioMedicine) gave mice Houttuynia water extract in drinking water for 4 weeks and found it lowered acetaminophen-induced cytochrome P450 2E1 activity and protected the liver. Whether that changes acetaminophen handling in people is untested.

Laxatives

The approved Japanese jūyaku label instructs users not to take other laxatives at the same time.

Metronidazole, tinidazole and disulfiram

Houttuynia tinctures contain ethanol, 20% to 24% in the NutraMedix product, or roughly 0.3 ml of alcohol per 30-drop serving. People taking disulfiram should avoid alcohol tinctures entirely, and the labels of metronidazole and tinidazole, both used in some Lyme and coinfection regimens, warn against alcohol during treatment and for days afterward.

Other injectables and "drip" products

Do not take any Houttuynia product sold for injection, intravenous infusion or nebulization outside a hospital that holds a current approval for it.

Quality, Testing & Adulteration

The aristolochic acid question

Houttuynia is not an Aristolochia and does not appear to make aristolochic acid itself, but its aristolactams share a Chinese name stem with aristolochic acids, and that drove public concern in greater China. At least three surveys have looked for the nephrotoxic acids directly, and another group quantified the aristolactams:

• Chan and colleagues (2020, Journal of Mass Spectrometry, Hong Kong University of Science and Technology): 20 fresh and sun-dried samples from cities across China, analyzed by LC-MS/MS with a method detection limit of 2 nanograms per gram. Aristolochic acids I and II were not detected in any sample. That result means below 2 ng/g, not zero.

• Yu and colleagues (2022, Foods, Nanchang University): 22 samples from 22 regions of China. Aristolochic acid I, aristolochic acid II and aristolactam I were not detected in any; aristolactam AII, which the authors note has not been reported to be genotoxic, was found in all 22.

• Wu and colleagues (2022, Molecules, China's National Institutes for Food and Drug Control): 75 batches from different origins. No aristolochic acids were found at a detection limit of 4 ng/mL or lower, while aristolactams AII, FI and BII were quantified.

• Xu and colleagues (2023): aristolactams AII, FI and BII quantified across 30 batches, with half-maximal toxic concentrations of 3.88 to 20.63 micromolar in human kidney tubule (HK-2) cells, comparable to aristolactam I.

The practical risk is therefore not contamination with aristolochic acid in clean material but the plant's own aristolactams, whose in-cell toxicity is real and whose in-body toxicity in mice was much lower than aristolochic acid's.

Injection quality

The injections were a manufacturing problem as much as a botanical one. Beijing Review quoted an expert in 2009 saying the quality of Yuxingcao injection "can vary considerably" across more than 100 factories. A 2010 Hong Kong Baptist University review of 210 published adverse-event reports (Bian and colleagues) found that 199 had no abstract and that most did not record the manufacturer, batch number or expiry date, which left many reactions untraceable to a manufacturer or batch.

Third-party testing

Neither USP, NSF nor ConsumerLab appears to run a Houttuynia-specific testing program, and no published survey of aristolactams in US Houttuynia supplements. A certificate of analysis that lists only identity, microbial counts and heavy metals says nothing about aristolactams.

What you can check yourself

• Plant part. The top of the aristolactam range for aerial parts was about nine times the top of the range for underground parts in the Xu data; a label that names "herb" or "aerial parts" is the higher-exposure material.

• Solvent and ratio. A label should state water, ethanol percentage or glycerin, and a herb-to-extract ratio. The NutraMedix label states the ethanol range but not the ratio.

• Aristolochic acid result with its detection limit. Ask the seller for a test result for aristolochic acids I and II and the limit of detection. "Not detected" at 2 ng/g means something; "not detected" with no stated limit means little.

• Route. Anything labeled for injection, infusion or nebulization is outside the supplement category entirely.

• Identity. A crushed leaf of genuine Houttuynia smells strongly fishy; dried powder in a capsule cannot be checked that way, which is a reason to prefer a seller that reports botanical identity testing.

Special Considerations

People with Lyme disease and coinfections

This is the group most likely to buy Houttuynia in the US and the group with the least evidence behind it. I found no study of Houttuynia taken alongside antibiotics or other herbal tinctures, or taken for longer than 8 weeks.

Children

The rhinitis trial enrolled only adults aged 20 to 60, and none of the oral trials described here reported results in children. The pediatric injection record is covered in Section 7.

COVID-19 and respiratory epidemics

Houttuynia was used during SARS in 2003 and again during COVID-19. A retrospective study of 123 Beijing SARS patients (Li and colleagues, 2006, American Journal of Chinese Medicine) compared Western treatment alone with Western treatment plus Herba Houttuyniae injection and, when needed, individualized herbs: hospital stay was longer with the combination, and mortality was 9.6% versus 11.1%, a difference that was not statistically significant. A 2023 observational report from a tribal community (Rahim and colleagues, Euroasian Journal of Hepato-Gastroenterology) linked regular use of the plant to COVID-19 outcomes but stated that "a conclusion cannot be reached due to small sample size."

Regulatory status outside China

In Japan, dried jūyaku is sold as a Class 3 over-the-counter laxative. In the US, Houttuynia tinctures and capsules are sold as dietary supplements without pre-market review, and the injections have never been approved.

Research Status & Evidence Quality

Moderate evidence

• The injected form causes anaphylactoid and anaphylactic reactions, sometimes fatal, more often by the intravenous route. This rests on thousands of spontaneous reports, a systematic review of 1,232 cases, mechanistic work on houttuynin protein adducts and MRGPRX2, and regulatory action.

• Aristolochic acids I and II were not detected in Houttuynia in surveys of 20, 22 and 75 samples, the first at a 2 ng/g limit.

Limited evidence

• Oral multi-herb formulas containing Houttuynia for chronic sinusitis: two randomized trials with 97 and 53 completers, one against placebo (no difference) and one against erythromycin (no difference).

• An 11-herb tea for allergic rhinitis: one open-label trial with 42 completers.

• A 13-herb patent medicine containing Houttuynia (Lianhua Qingwen) for non-influenza viral pneumonia: one placebo-controlled trial with a modest symptom benefit.

• First-episode ulcerative colitis: one comparison of 21 versus 21 patients, with an unspecified preparation and no blinding described.

Preclinical only

• Antiviral, antibacterial, anti-biofilm, anti-asthma, anti-obesity, liver-protective and anticancer effects, from cell culture and rodent work. A 2026 review in Current Nutrition Reports (Karmakar and colleagues) concluded that the evidence for metabolic syndrome "remains limited."

• Kidney and liver toxicity at high doses of ethanol extract, and aristolactam cytotoxicity, from rats, mice and cultured cells.

No evidence

• Lyme disease, Borrelia, Bartonella, Mycoplasma, or "biofilm" infection in humans.

Research Limitations

Most oral trials test Houttuynia inside formulas of 2 to 13 herbs, so its own contribution is unmeasured. Several Chinese-language studies report only abstracts in English, without preparation details. The injection literature suffers from poor reporting, as the 2010 Bian review documented, and spontaneous-report counts cannot give an incidence rate because the number of patients injected is unknown. No study I found has measured houttuynin, 2-undecanone or aristolactams in human blood after an oral dose.

Summary & Key Takeaways

Bottom Line

Houttuynia cordata is a widely eaten vegetable with a dangerous injectable past and a thin oral evidence base. A placebo-controlled oral trial in post-surgical sinusitis found no benefit; the positive trials are mostly small, one is open-label, and they test multi-herb formulas or an unspecified preparation. The Lyme, antiviral and biofilm claims attached to Western tinctures rest on herbalist recommendation and cell-culture work with a semi-synthetic derivative.

Key Safety Points

• Never inject any Houttuynia product or use one by a route its label does not state; injection reactions began within one minute in the fastest documented cases.

• Avoid it entirely if you ever reacted to a Houttuynia or sodium houttuyfonate injection.

• Avoid it during pregnancy and breastfeeding, and with reduced kidney function.

• Prefer water-based preparations and the rhizome over alcohol extracts of flowering tops if aristolactam exposure concerns you.

• Do not let a tincture delay antibiotic treatment for a tick-borne infection.

Special Note

If a Houttuynia tincture is part of a long Lyme protocol, tell the prescribing clinician, list every other tincture by name and ethanol content, and set a stop date rather than taking it indefinitely.

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Researched and drafted with AI assistance. Every claim verified against primary sources and human-reviewed before publication. Last reviewed: November 7, 2026. Corrections: reply to any issue.

This issue is for education only and is not medical advice. If you take prescription medication, are pregnant, or live with a diagnosed condition, talk with a clinician before starting, stopping or changing any supplement.