Yu Xing Cao
StarHouttuynia cordata
Traditionally used for
- Cough & breathing
- Urinary & fluids
- Skin
Cautions & contraindications
- Allergy risk
- Toxic — professional use only
☯ TCM Properties
Clears Heat, relieves toxicity, reduces swellings and abscesses and expels pus (especially on the Lungs); Drains Damp-Heat and promotes urination
Traditional Chinese Uses
Yu Xing Cao (fish mint, houttuynia herb) is a cold, slightly toxic herb considered one of the most important Heat-toxin-clearing herbs in Chinese medicine, especially for Lung and skin conditions. It is the primary herb for Lung abscess with purulent phlegm and is widely used for Lung Heat cough with thick yellowish-green sputum. Its anti-inflammatory and antimicrobial properties are also applied for Damp-Heat skin sores, urinary tract infections, and inflammatory conditions of the lower body.
Western Herbalism Properties
Relationships
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Botanical Description
Houttuynia cordata is a perennial aromatic herb with creeping rhizomes, growing 15-50 cm tall. Stems are reddish, grooved, and rooting at nodes. Leaves are heart-shaped (cordate), 4-10 cm long, alternate, with a pungent fishy odor when crushed. The inflorescence consists of a slender spike of tiny yellow flowers subtended by 4 white petal-like bracts. The plant spreads vigorously through rhizomes. The characteristic fishy smell is due to decyl acetate and other volatile compounds.
Moist shaded areas, stream banks, rice paddies, swamps, and wetland margins; native to Southeast Asia and widely distributed throughout East and Southeast Asia.
Houttuynia cordata is extremely common throughout its native range in East and Southeast Asia. It is considered invasive in parts of North America and Europe. No conservation concerns.
Active Constituents
Houttuynin (decanoyl acetaldehyde)
Aliphatic beta-keto aldehyde (essential oil constituent)Concentration: Reported at roughly 44 percent of the pure essential oil in one validated assay, but under 1 percent and often undetectable in commercial injection formulations because it degrades during hydrodistillation
The principal antibacterial component of the volatile oil, with inhibitory activity against Staphylococcus aureus, Escherichia coli and other pathogens. It is chemically unstable, oxidising and polymerising readily, which is why the manufactured sodium bisulfite adduct exists and why assays of finished products often fail to find it.
2-Undecanone (methyl nonyl ketone)
Aliphatic methyl ketoneConcentration: A major component of the essential oil, reported at roughly one fifth of the oil in GC-MS analyses; standardised at 9.8 micrograms per mL in the Houttuynia eye drop tested in a published randomised trial
A broad-spectrum antibacterial ketone with reported anti-inflammatory and antitumour activity, and the compound nominated as the main effective component of the aqueous eye drop preparation studied in meibomian gland dysfunction. Being more stable than houttuynin, it is the more practical marker for finished products.
Quercitrin (quercetin 3-O-rhamnoside)
Flavonol glycosideConcentration: One of the dominant flavonoids of the aerial herb, alongside hyperoside, rutin and isoquercitrin
A water-soluble flavonol glycoside that carries much of the antioxidant and anti-inflammatory activity of the decoction. Unlike the volatile oil constituents it survives boiling, so it is the fraction most likely to be present when the herb is taken as a tea or in a decoction.
Hyperoside (quercetin 3-O-galactoside)
Flavonol glycosideConcentration: A major flavonoid of the aerial parts
Contributes with quercitrin and rutin to the antioxidant and capillary-stabilising activity attributed to the flavonoid fraction of the herb.
Aristolactam A II
Phenanthrene lactam alkaloid (aristolactam)Concentration: Detected in all 22 Chinese samples surveyed by UHPLC-QTOF-MS at 0.67 to 17.24 mg/kg; the three aristolactams together reach 3.20 to 108.19 micrograms per gram, concentrated in the aerial parts and especially the flowers
Houttuynia cordata contains aristolactams A II, B II and F I. This matters because their Chinese name resembles that of the aristolochic acids, and it has caused public alarm. The distinction is real and important: aristolochic acid I and aristolochic acid II, the IARC Group 1 carcinogens, have repeatedly been sought in this herb and were not detected, and aristolactam I was also absent. The aristolactams that are present did show cytotoxicity to renal cells in vitro with IC50 values of 3.88 to 20.63 micromolar, comparable to aristolactam I, yet the same study found no detectable aristolactams in water extracts, and in vivo work found only modest changes in renal markers compared with the marked injury caused by aristolochic acid I.
Sodium houttuyfonate
Semi-synthetic sodium bisulfite adduct of houttuyninConcentration: Not a natural constituent; a manufactured stabilised derivative used in Chinese pharmaceutical preparations
Made to overcome the instability of houttuynin, and used in oral and injectable Chinese products. It should not be treated as equivalent to the crude herb: it is a manufactured single entity with its own safety record, and it is one of the components implicated in reactions to the injectable products.
⚠ Drug Interactions
Houttuynia cordata injection and other injectable Houttuynia preparations
Houttuynia injection was approved for intramuscular use in China in 1978 and for intravenous use in 1994. The Chinese national adverse reaction monitoring centre logged more than 5000 adverse reactions between 1988 and April 2006, including 222 serious cases, and fatal anaphylaxis was reported in the peer-reviewed literature. On 1 June 2006 the State Food and Drug Administration suspended use and approval of seven Houttuynia injectable preparations. Manufacture was later permitted again for a limited number of producers and, after re-evaluation, essentially for the intramuscular form, with an allergen warning added to the labelling. Among 315 patients with reactions in one series the commonest features were dyspnoea, change of complexion and cardiac abnormality. The mechanism is largely pseudo-allergic rather than IgE-mediated: mast cell activation through the MRGPRX2 receptor, shown by loss of the reaction in Mrgprb2 knockout mice, with the solubiliser polysorbate 80 identified as a contributor above about 0.01 mg/mL in dog experiments.
Clinical note: Keep the oral herb and the injection completely separate in your mind and in your notes. The dried herb in decoction and the fresh leaf as a vegetable are ordinary food-grade exposures with no comparable record. Injectable Houttuynia should not be sought, imported or administered outside a Chinese hospital setting with resuscitation facilities. Ask any patient reporting a past severe reaction to a Chinese herbal drip whether it was Houttuynia, and record it as a drug allergy.
Aristolochic acid-containing herbs (Aristolochia and Asarum species) and other nephrotoxins
The aristolactams of Houttuynia cordata are structurally related to aristolactam I, the nephrotoxic metabolite of aristolochic acid, and were cytotoxic to renal cells in vitro at low micromolar concentrations with induction of oxidative stress and fibrosis markers. The reassuring qualifiers are substantial: aristolochic acids I and II are not detectable in the herb, aristolactam I itself was not detected, the aristolactams are concentrated in flowers and aerial tissue rather than distributed evenly, water extracts contained none that could be measured, and in vivo the effect was far smaller than that of aristolochic acid I. The residual concern is real but modest, and applies to alcoholic extracts, flowering material and long uninterrupted use rather than to short courses of decoction.
Clinical note: Prefer decoction over alcohol extract, prefer pre-flowering harvested herb, avoid open-ended long-term dosing, and do not stack this herb with any Aristolochia or Asarum-containing formula. Check renal function before prolonged use in patients with existing chronic kidney disease or on other nephrotoxic drugs.
Conventional prescription medicines metabolised by cytochrome P450 enzymes
No study of Houttuynia cordata alone has established a clinically relevant cytochrome P450 interaction. The available in vitro work tested CP-001, a standardised four-herb mixture containing Houttuynia cordata with Rehmannia glutinosa, Betula platyphylla and Rubus coreanus, and found only slight inhibition of some isozymes with IC50 values above 100 micrograms per mL and no time-dependent inhibition. Because the herb was not tested alone, that result cannot be attributed to Houttuynia, and it should be read as an absence of evidence rather than as evidence of safety.
Clinical note: No specific monitoring is indicated. Record this as unstudied rather than as cleared, and apply ordinary caution with narrow-therapeutic-index drugs.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 15–25 g | daily | — | adult | 中国药典 2020年版 一部 【鱼腥草】【用法与用量】15～25g，不宜久煎；鲜品用量加倍，水煎或捣汁服。外用适量，捣敷或煎汤熏洗患处。 — Chinese Pharmacopoeia 2020, Vol. I. Add near end of cooking and do not decoct long, to preserve the volatile oil. |
Evidence Tier
Strong evidence · 8 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
1
1 verified · 0 unverified
Show the study
Randomized controlled trial
2
1 verified · 1 unverified
Show 2 studies
- Efficacy and Safety of Houttuynia Eye Drops Atomization Treatment for Meibomian Gland Dysfunction-Related Dry Eye Disease: A Randomized, Double-Blinded, Placebo-Controlled Clinical Trial
- A Houttuynia cordata–based Chinese herbal formula improved symptoms of allergic rhinitis during the COVID-19 pandemic
Other clinical trial
0
Observational / case report
1
0 verified · 1 unverified
In vitro / animal
4
1 verified · 3 unverified
Show 4 studies
- Mrgprb2 gene plays a role in the anaphylactoid reactions induced by Houttuynia cordata injection
- In vitro nephrotoxicity and quantitative UPLC-MS analysis of three aristololactams in Houttuynia cordata
- Analysis of aristolochic acids in Houttuynia cordata by liquid chromatography–tandem mass spectrometry
- Study of the Contents of Analogues of Aristolochic Acid in Houttuynia cordata by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Anaphylactic shock and lethal anaphylaxis caused by Houttuynia Cordata injection, a herbal treatment in China
Reports anaphylactic shock and fatal anaphylaxis attributed to Houttuynia cordata injection as used in China, with laboratory investigation of the reactions. This is the key English-language reference establishing that the parenteral preparation, not the oral herb, has killed patients.
Adverse events to Houttuynia injection: A systematic review
Systematic review of adverse events reported with Houttuynia injection, published after the 2006 Chinese regulatory suspension. Anaphylactoid reactions dominate the reported harms, and dyspnoea, change of complexion and cardiac abnormality were the commonest features among the pooled cases.
Mrgprb2 gene plays a role in the anaphylactoid reactions induced by Houttuynia cordata injection
Using Mrgprb2 knockout mice, the authors showed that the reactions to Houttuynia cordata injection depend on the Mrgprb2 receptor, the rodent counterpart of human MRGPRX2. This places the reactions in the mast-cell pseudo-allergy category rather than classical IgE hypersensitivity, which explains why they can occur on first exposure and without prior sensitisation.
Efficacy and Safety of Houttuynia Eye Drops Atomization Treatment for Meibomian Gland Dysfunction-Related Dry Eye Disease: A Randomized, Double-Blinded, Placebo-Controlled Clinical Trial
Multi-centre randomised double-blind placebo-controlled trial in 240 patients with meibomian gland dysfunction-related dry eye, using once-daily atomisation of Houttuynia eye drops for four weeks. Eye symptom score, meibum quality and tear break-up time all improved more than with placebo, with modest effect sizes, and no medication-related adverse events were observed. This is a topical ophthalmic preparation, not the oral herb.
A Houttuynia cordata–based Chinese herbal formula improved symptoms of allergic rhinitis during the COVID-19 pandemic
Randomised controlled trial of a four-week course of a Houttuynia cordata-based multi-herb formula in allergic rhinitis. Participants improved on nasal obstruction, nasal secretion, reduced smell and postnasal drip compared with control. As a multi-herb formula the result cannot be attributed to Houttuynia alone, but it is one of the few controlled oral human studies in which the herb is the named principal ingredient.
In vitro nephrotoxicity and quantitative UPLC-MS analysis of three aristololactams in Houttuynia cordata
Isolated aristolactams A II, B II and F I from Houttuynia cordata and found they were cytotoxic to renal cells with IC50 values from 3.88 to 20.63 micromolar, comparable with aristolactam I, inducing oxidative stress and fibrosis markers. Across 30 samples the aristolactams were concentrated in aerial parts and especially flowers at 3.20 to 108.19 micrograms per gram, and were not detectable in water extracts. The last finding is the one that matters most for practice, since decoction is the usual route of administration.
Analysis of aristolochic acids in Houttuynia cordata by liquid chromatography–tandem mass spectrometry
Applied LC-MS/MS specifically to look for aristolochic acids in Houttuynia cordata. Aristolochic acid I and aristolochic acid II were not detected, separating the herb from the genuinely carcinogenic aristolochic acid-containing drugs with which its aristolactam content has caused it to be confused.
Study of the Contents of Analogues of Aristolochic Acid in Houttuynia cordata by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry
Surveyed 22 Houttuynia cordata samples from different Chinese regions. Aristolochic acid I, aristolochic acid II and aristolactam I were undetectable in every sample, while aristolactam A II was present in all of them at 0.67 to 17.24 mg/kg. The authors note that aristolactam A II has not been reported to be genotoxic.
Historical Texts
Ming Yi Bie Lu
Six Dynasties, compiled around 500 CEZhonghua Renmin Gongheguo Yaodian (Pharmacopoeia of the People's Republic of China)
Modern, 2020 editionReferences
- Ji Hoon Yang, Eun Ju Hwang, Jungyoon Moon, Ji Young Yoon, Ji Won Kim, Sungjun Choi, Soo Ick Cho, Dae Hun Suh. Clinical efficacy of herbal extracts in treatment of mild to moderate acne vulgaris: an 8-week, double-blinded, randomized, controlled trial . Journal of Dermatological Treatment (2021) [DOI]
- In Gyoung Ju, Seungmin Lee, Jin Gyu Choi, Namkwon Kim, Eugene Huh, Jong Kil Lee, Myung Sook Oh. Aerial part of Houttuynia cordata reverses memory impairment by regulating amyloid beta accumulation and neuroinflammation in Alzheimer's disease model . Phytotherapy Research (2023) [DOI]
- Jun Li, Futao Zhao. Anti-inflammatory functions of Houttuynia cordata Thunb. and its compounds: A perspective on its potential role in rheumatoid arthritis . Experimental and Therapeutic Medicine (2015) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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