Tu Yin Chen
StarOriganum vulgare L.
Synonyms: Thymus origanum (L.) Kuntze, Origanum vulgare subsp. vulgare, Origanum normale D.Don
Traditionally used for
- Headaches
- Colds & fever
- Digestion
- Liver & jaundice
☯ TCM Properties
Induces diaphoresis , eliminates Dampness; Regulates Qi
Traditional Chinese Uses
Written to the scientific name Origanum vulgare (oregano), known in Chinese medicine as Niu Zhi, this is an aromatic herb classed among the Dampness-transforming medicinals. Pungent and cool, it releases the Exterior and induces mild sweating, transforms and eliminates Dampness, regulates Qi and clears summer-heat. It is used for summer-damp colds with fever, headache, chest oppression and poor appetite, for damp-heat patterns, and—reflecting the name “Tu Yin Chen” (local Yin Chen)—as a regional substitute for Yin Chen (Artemisia capillaris) in damp-heat jaundice. It is usually decocted at 3–9 g or taken as a medicinal tea.
“Tu Yin Chen” is a regional folk name applied to several unrelated substitute plants, so the botanical source should be verified before use.
Relationships
Full-screen graph →Click a node for details · double-click to expand it · Ctrl/⌘ + scroll or two fingers to zoom and pan.
Botanical Description
Tu Yin Chen is the aerial part of Origanum vulgare (Lamiaceae), oregano or wild marjoram, an aromatic perennial herb 30 to 80 centimetres tall. The erect, four-angled stems are often purplish and softly hairy, branching in the upper part. The opposite, short-stalked leaves are ovate, 1 to 4 centimetres long, entire or faintly toothed and dotted with translucent oil glands that release a warm, pungent aroma when crushed. Small two-lipped flowers, pale purple-pink to whitish, are crowded into dense, flat-topped corymbose panicles subtended by conspicuous purple-tinged bracts. The fruit comprises four tiny smooth nutlets. The whole flowering herb is collected in summer and dried for use.
Grows on sunny grassy slopes, thickets, roadsides and forest margins from lowlands to about 3600 m across temperate Eurasia, including much of China.
Active Constituents
Carvacrol
Monoterpenoid phenolConcentration: The major essential oil component in carvacrol-chemotype material; content swings from dominant to nearly absent between subspecies and chemotypes of the same species
The principal antimicrobial of oregano oil, acting by damaging the bacterial cytoplasmic membrane, depleting ATP, inhibiting efflux pumps and suppressing biofilm formation. It was the major compound in essential oil from wild Italian Origanum vulgare, and it is also the constituent named in the case report of oregano infusion raising the INR of an anticoagulated patient.
Thymol
Monoterpenoid phenolConcentration: Dominant in thymol-chemotype material; in Origanum vulgare subsp. virens, thymol-rich, carvacrol-rich and mixed chemotypes all occur within the one subspecies
An isomer of carvacrol with the same broad antimicrobial mechanism, and the more active of the two against several phytopathogenic fungi in comparative chemotype work. Thymol was the stronger alpha-glucosidase inhibitor of the two in enzyme assays, which is the basis of the theoretical concern about additive effects with oral hypoglycaemics.
p-Cymene
Monoterpene hydrocarbonConcentration: A consistent essential oil component; proportions vary widely with chemotype and origin
The biosynthetic precursor of carvacrol and thymol and a routine marker in oregano oil chromatograms. Weakly active on its own; it matters mainly because a high p-cymene to phenol ratio marks oil that has not accumulated the active phenols.
gamma-Terpinene
Monoterpene hydrocarbonConcentration: A consistent essential oil component alongside p-cymene
Upstream of p-cymene in the pathway to the phenolic monoterpenes. Its abundance in an oil is a sign of an immature or low-phenol chemotype rather than of potency.
Rosmarinic acid
Caffeic acid ester (phenylpropanoid)Concentration: The predominant compound in the methanolic extract of leaves and inflorescences of wild Italian material
The main non-volatile polyphenol and the reason the water or alcohol extract, not the essential oil, carries most of the antioxidant activity. The methanolic extract was substantially more potent than either the wild or commercial essential oil across DPPH, ABTS and FRAP assays, and protected HepG2 cells against oxidative DNA damage without reducing proliferation.
Flavonoids including apigenin and luteolin derivatives
Flavones and flavone glycosidesConcentration: Part of the non-volatile phenolic fraction; individual contents not consistently quantified across origins
Together with the phenolic acids these make up the polyphenol fraction credited in the case-report literature with cytochrome P450 inhibition, particularly CYP2C9 and CYP3A4. That attribution is a mechanistic inference, not a measured inhibition constant for this herb.
⚠ Drug Interactions
Acenocoumarol, warfarin and other vitamin K antagonists
A 77-year-old woman in atrial fibrillation, stable on acenocoumarol with an INR in range for four years and compliant with dietary advice, drank one 200 ml cup of oregano infusion a day (with occasional verbena) for a week. Her routine INR came back at 6.42. Stopping the herbal tea brought the INR to 3.80 the next day and to 2.5 four days after the anticoagulant was restarted. She resumed the infusion, the effect recurred, and stability was regained only by diluting the infusion and reducing the acenocoumarol dose. The authors attribute it to two additive mechanisms: inhibition of CYP2C9 and CYP3A4 by the polyphenols, tannins and flavonoids, and direct anticoagulant activity of carvacrol and thymol. This is a single case, but it carries a positive dechallenge and a positive rechallenge, and both plants in the infusion pull the same way.
Clinical note: Ask anticoagulated patients specifically about oregano tea, not just about supplements — a garden herb infusion does not read to patients as medicine. If the herb is used at all, keep the preparation and quantity constant, check INR within a week of starting or stopping, and expect the anticoagulant dose to need reducing.
Artemisia capillaris (Yin Chen, Yin Chen Hao)
Tu Yin Chen is a regional folk name for Origanum vulgare, recorded for Fujian, with Bai Hua Yin Chen used in Jiangxi and Yunnan and Tu Xiang Ru in Guizhou. It is not Yin Chen. Yin Chen, Artemisiae Scopariae Herba, is the Asteraceae drug from Artemisia capillaris or Artemisia scoparia, and it is the principal Chinese herb for damp-heat jaundice, backed by a pharmacopoeial monograph and a large choleretic literature. Origanum vulgare is a Lamiaceae aromatic with an essential oil of carvacrol and thymol and no comparable jaundice evidence. The two plants share nothing beyond the syllables Yin Chen and a folk reputation for damp conditions. Substituting Tu Yin Chen for Yin Chen in a jaundice prescription replaces the treated drug with an untested one.
Clinical note: Never fill Yin Chen with Tu Yin Chen or the reverse. Confirm the family from the material itself: Origanum is an aromatic square-stemmed Lamiaceae with a strong oregano odour; Artemisia capillaris is a fine-leaved Asteraceae. Where the prescription is for jaundice, insist on the pharmacopoeial Artemisia drug.
Elsholtzia ciliata (Xiang Ru)
Origanum vulgare also carries the Guizhou name Tu Xiang Ru and is regionally called Chuan Xiang Ru, which sets it against Xiang Ru, the Lamiaceae drug from Elsholtzia or Mosla species used for summerheat-damp with exterior chill. Both are aromatic Lamiaceae, so the substitution is not obvious on the bench the way the Artemisia one is, and the two have overlapping but not identical traditional indications. Modern textual research on the Chinese materia medica suggests some pre-modern Xiang Ru and Yin Chen entries may in fact describe this species, which is why the folk names accumulated in the first place.
Clinical note: Specify the binomial. If aromatic Lamiaceae material arrives against an order for Xiang Ru, confirm the genus before dispensing, since Origanum and Elsholtzia are not interchangeable in a summerheat formula.
Origanum vulgare subsp. hirtum and other oregano oil sources
Most of the antimicrobial literature marketed as evidence for oregano was generated on the phenol-rich subspecies, chiefly Origanum vulgare subsp. hirtum, or on high-carvacrol chemotypes. Within the single subspecies virens, thymol-rich, carvacrol-rich and mixed thymol-carvacrol chemotypes all occur and behave differently in antifungal, antifeedant and enzyme-inhibition assays. A product labelled Origanum vulgare L. therefore says nothing about its carvacrol content, and dose carried across from a published trial may be far too little or far too much.
Clinical note: For any antimicrobial use, require a certificate of analysis giving carvacrol and thymol percentages, and do not transfer a dose from a study without checking that the oil composition matches. Treat the crude aerial herb and the essential oil as different preparations with different dose ranges.
Ampicillin, gentamicin, tetracycline and tobramycin
Against Staphylococcus aureus, oregano essential oil alone had a minimum inhibitory concentration of 0.312 mg/mL, and checkerboard and time-kill assays showed synergy when it was combined with ampicillin, gentamicin, tetracycline or tobramycin, reducing the antibiotic MICs. The combinations also inhibited biofilm formation and downregulated the quorum-sensing genes agrA, hld, RNAIII and rot. This is a broth study on isolates; nothing has been shown about systemic exposure in a patient, and the concentrations are not achievable in blood by drinking a tea.
Clinical note: Do not represent oregano as an antibiotic potentiator to patients, and do not reduce a prescribed antibiotic dose on the strength of it. The finding is relevant to topical and surface applications, not to systemic infection.
Oral hypoglycaemic agents
Thymol was the strongest alpha-glucosidase inhibitor among the oregano oil constituents tested in comparative enzyme assays, the same target as acarbose. No human or animal glycaemic study of the herb exists, and enzyme inhibition in a cuvette does not establish a postprandial effect.
Clinical note: In a patient on acarbose or a sulfonylurea who begins taking oregano preparations regularly, monitor postprandial glucose rather than assuming the herb is inert. Do not use it as a glucose-lowering agent.
Evidence Tier
Moderate evidence · 5 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
0
Randomized controlled trial
1
0 verified · 1 unverified
Other clinical trial
0
Observational / case report
1
1 verified · 0 unverified
In vitro / animal
3
0 verified · 3 unverified
Show 3 studies
- Antimicrobial effects of essential oil from Origanum vulgare in combination with conventional antibiotics against Staphylococcus aureus
- Phytochemistry and Bioactivity of Essential Oil and Methanolic Extracts of Origanum vulgare L. from Central Italy
- Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens Essential Oils: Chemotypes and Bioactivity as Antifungal, Antifeeding and Enzyme Inhibitors
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
Efficacy of an Herbal Vaginal Tablet Containing Oregano and Lemon Balm on Bacterial Vaginosis in Comparison to Metronidazole: a non-inferiority triple-blind active-controlled trial
A non-inferiority triple-blind active-controlled trial in 130 women with bacterial vaginosis comparing a vaginal tablet of alcoholic extracts of oregano aerial parts and lemon balm leaves against metronidazole vaginal tablets. No significant difference between groups in clinical signs, symptoms or Amsel's criteria at day 5 or day 10. Note this is a two-herb vaginal formulation, so nothing here supports oral oregano, and attrition was heavy by day 10 (28 and 31 completers).
SmartGel OV: A Natural Origanum vulgare-Based Adjunct for Periodontitis with Clinical and Microbiological Evaluation
Thirty adults with periodontitis applied an Origanum vulgare essential oil gel daily by gingival massage for four months. Fusobacterium nucleatum and Capnocytophaga species fell significantly and probing depth, bleeding on probing and plaque index improved. Uncontrolled and observational, with no comparator, so regression to the mean and the massage itself are not excluded.
Antimicrobial effects of essential oil from Origanum vulgare in combination with conventional antibiotics against Staphylococcus aureus
Of ten essential oils from Calabrian aromatic plants, only oregano oil strongly inhibited Staphylococcus aureus, with an MIC of 0.312 mg/mL. Checkerboard and time-kill assays showed synergy with ampicillin, gentamicin, tetracycline and tobramycin; at half-MIC the combinations inhibited biofilm formation and downregulated the quorum-sensing genes agrA, hld, RNAIII and rot, with measurable shifts in bacterial adenine and cytosine methylation.
Phytochemistry and Bioactivity of Essential Oil and Methanolic Extracts of Origanum vulgare L. from Central Italy
GC-MS and UHPLC-DAD on wild leaves and inflorescences from central Italy found carvacrol dominant in the essential oil and rosmarinic acid dominant in the methanolic extract. The methanolic extract was far the strongest antioxidant (DPPH IC50 0.052 mg/mL) against a commercial oil (0.45 mg/mL) and the wild oil (1.54 mg/mL). Neither preparation was toxic to HepG2 cells at the doses tested, and pre-treatment reduced the oxidative DNA damage marker 8-OHdG.
Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens Essential Oils: Chemotypes and Bioactivity as Antifungal, Antifeeding and Enzyme Inhibitors
Three chemotypes within a single subspecies, thymol-rich, carvacrol-rich and mixed, were characterised and compared. All inhibited Alternaria alternata, Botrytis cinerea and Fusarium oxysporum above 0.5 mg/mL, with the thymol-rich chemotype strongest. Carvacrol was the better acetylcholinesterase inhibitor and thymol the better alpha-glucosidase inhibitor. The practical message is that the species name does not predict the oil's composition or its activity.
Historical Texts
Zheng Lei Ben Cao (Classified Materia Medica), Tang Shenwei
Northern Song dynasty, c. 1108Dian Nan Ben Cao (Materia Medica of Southern Yunnan), Lan Mao
Ming dynasty, 1436Zhonghua Ben Cao (Chinese Materia Medica), State Administration of Traditional Chinese Medicine
Modern, 1999Pharmacopoeia of the People's Republic of China
Modern, current 2020 editionReferences
- Beghriche I, Belhachem A, Hamidene I, Fendri AH. Origanum vulgare et risque hémorragique, à propos d'un cas . Annales de Cardiologie et d'Angéiologie (2025) [DOI]
- Soltani S, Shakeri A, Iranshahi M, Boozari M. A Review of the Phytochemistry and Antimicrobial Properties of Origanum vulgare L. and Subspecies. . Iranian Journal of Pharmaceutical Research (2021) [DOI]
- Ortiz-Mendoza N, Martínez-Gordillo MJ, Martínez-Ambriz E, Basurto-Peña FA, González-Trujano ME, Aguirre-Hernández E. Ethnobotanical, Phytochemical, and Pharmacological Properties of the Subfamily Nepetoideae (Lamiaceae) in Inflammatory Diseases . Plants (2023) [DOI]
- Yin T, Guo H, Zhu Y, Yang Y, Hao H, Liu X, Lou J, Xie C, Wang Y, Yan H, Huang L, Li Y, Yan S, Chi Y, Xu B, Zhang J. Chromosome-level genome assembly of Origanum vulgare subsp. hirtum reveals evolutionary insights and regulatory modules in terpenoid biosynthesis . Horticulture Research (2026) [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.
📝 Notes
Public notes from the community and your own private notes on Tu Yin Chen.
No notes yet.