Oregano
Summary
Oregano oil is sold for gut, immune and infection support, but human evidence is thin. An uncontrolled study of 14 people with gut parasites reported clearance in many cases, a small trial found an oregano ointment reduced bacteria on surgical wounds, and two small trials reported better cholesterol markers (all grade D). Allergy to oregano and related mints occurs.
Key facts
- A Mediterranean herb; its essential oil is high in carvacrol (68–82% in two oregano oils tested)[7]
- Gut parasites (D, uncontrolled), surgical wound bacteria with ointment (D), cholesterol markers (D)[3][4][5][7]
- FDA lists Origanum essential oils and extractives as generally recognized as safe for their intended use in food[1]
- 600 mg/day of emulsified oregano oil for 6 weeks in the parasite study[3]
- 1–2 mg/kg/day of carvacrol for a month kept blood and urine tests within normal ranges in healthy adults[6]
- Systemic allergic reactions to oregano and thyme, with cross-sensitivity to other mint-family herbs, have been reported[8]
- 4 graded human outcomes on this page
- October 10, 2026
How it works
ProposedCarvacrol, the main phenol in oregano oil, is antimicrobial and antioxidant in laboratory and animal studies, though human trials are lacking; in people, a 3% oregano ointment reduced Staphylococcus aureus on surgical wounds.[4][9]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Cholesterol | Grade D | Improved | Open-label · n = 48 · 2008 | 2 rows |
| Skin wounds | Grade D | Improved | RCT · n = 40 · 2011 | 1 row |
| Gut parasites | Grade D | Improved | Open-label · n = 14 · 2000 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Cholesterol and endothelial function in mild high cholesterol | Improved | Grade D | Open-label trial · n = 48 · 2008 Adults with mild hyperlipidaemia not needing drugs Form: Aqueous distillate of Origanum onites, plus diet advice · Dose: 25 mL after each meal · Duration: 3 months LDL, apolipoprotein B, lipoprotein(a) and hs-CRP fell and HDL rose more than in the diet-only control group; artery dilation improved. | 19094443 (opens PubMed)Source [5] |
| Bacteria and infection in surgical wounds | Improved | Grade D | RCT · n = 40 · 2011 Adults after surgical skin excision Form: 3% oregano extract ointment versus petrolatum · Dose: Applied to the wound · Duration: Followed to 90 days S. aureus grew in 19% of cultures with oregano versus 41% with petrolatum; 1 versus 3 people developed cellulitis. Scar colour, pigmentation and pliability scores favoured oregano, and overall scar appearance was equivalent. | 21968667 (opens PubMed)Source [4] |
| Blood lipids in athletes | Mixed | Grade D | RCT · n = 34 · 2022 Trained athletes Form: Oregano essential oils (Origanum dubium or O. vulgare subsp. hirtum, 68–82% carvacrol) · Dose: Not stated in the abstract · Duration: 14 days HDL rose with both oregano oils versus control, and LDL fell with O. dubium; total cholesterol, triglycerides and liver markers did not change. | 34496170 (opens PubMed)Source [7] |
| Gut parasites in stool | Improved | Grade D | Open-label trial · n = 14 · 2000 Adults whose stools tested positive for Blastocystis hominis, Entamoeba hartmanni or Endolimax nana Form: Emulsified oil of Mediterranean oregano (Origanum vulgare) · Dose: 600 mg/day · Duration: 6 weeks Entamoeba hartmanni (4 cases), Endolimax nana (1) and Blastocystis hominis (8) disappeared from stool, and Blastocystis scores fell in 3 more; gut symptoms improved in 7 of 11 with Blastocystis. | 10815019 (opens PubMed)Source [3] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Oregano essential oil (emulsified or in capsules) | Varies[3][7] | No human absorption data in our sources.[3] | No adverse effects reported in the 6-week parasite study abstract.[3] | Gut parasites (600 mg/day) and lipids in athletes |
| Oregano extract ointment (3%) | Varies[4] | No human absorption data in our sources.[4] | No safety concerns reported; fewer wound infections than petrolatum.[4] | Post-surgical wound bacteria |
| Aqueous oregano distillate (Origanum onites) | Varies[5] | No human absorption data in our sources.[5] | No safety problems reported in the abstract over 3 months.[5] | Cholesterol markers (25 mL after meals) |
| Isolated carvacrol | Varies[6][10] | No human absorption data in our sources.[6] | 1–2 mg/kg/day for one month: lab values stayed within normal ranges.[6] | Safety and small asthma trials |
Studied doses
Doses studied in human trials ranged from 600 mg/day of emulsified oregano oil for 6 weeks to 25 mL of oregano distillate after each meal for 3 months; essential oils were given for 14 days in athletes, and a 3% ointment was used on wounds.[3][5][7][4]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Allergy to oregano, thyme or other mint-family herbs
- Systemic allergic reactions to oregano and thyme have been reported, with cross-sensitivity to related herbs such as marjoram, sage, mint and hyssop.[8]
- Pregnancy and breastfeeding
- No human safety data for oregano oil supplements in pregnancy or breastfeeding were found; GRAS status covers food flavoring use.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Safety
Food amounts are generally recognized as safe; supplement-dose data are limited.
- Allergy
- Systemic reactions to oregano and thyme in one patient, with skin-test cross-reactivity across the mint family.[8]
- Carvacrol
- One month of carvacrol at 1–2 mg/kg/day kept blood, urine and lung tests within normal ranges in healthy adults, although several values (such as hemoglobin, HDL and some blood-cell indices) shifted significantly from baseline.[6]
- Liver markers
- Oregano essential oils for 14 days did not change liver biomarkers in athletes.[7]
How to read the label
- Label dose vs clinical doseThe parasite study used 600 mg/day of emulsified oil; many products list drops or "oil of oregano" without carvacrol content.[3]
- Food use vs supplement doseFDA GRAS listings cover Origanum essential oils and extractives for their intended use in food, not concentrated supplement doses.[1][2]
- Carvacrol content variesTwo oregano essential oils tested in one trial contained 68% and 82% carvacrol.[7]
- Species differ"Oregano" on US spice lists can mean Mexican oregano (Lippia spp.), a different plant from Origanum.[2]
Cost per studied dose, without the sales pitch
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Cost per studied dose
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Frequently asked questions
Does oregano oil kill gut parasites?
In an uncontrolled study of 14 adults, 600 mg/day of emulsified oregano oil for 6 weeks cleared parasites in many cases; no controlled trial confirms it.[3]
Does oregano ointment help surgical wounds?
A 3% oregano ointment reduced bacteria and infections on surgical wounds versus petrolatum in a 40-person trial, with similar overall scar appearance.[4]
Does oregano lower cholesterol?
Two small trials reported higher HDL or lower LDL with oregano distillate or oils, but neither was large or long.[5][7]
Is oregano oil safe?
Oregano oils are GRAS as food flavorings; supplement-dose safety data are limited, and allergic reactions occur in people sensitive to mint-family herbs.[1][8]
What is carvacrol?
The main phenol in oregano oil, making up 68–82% of the oils tested in one trial.[7]
Sources
- [1]21 CFR 182.20: Essential oils, oleoresins (solvent-free), and natural extractives (including distillates) generally recognized as safe (lists Origanum spp.). U.S. Food and Drug Administration (Electronic Code of Federal Regulations), 2026. guideline
- [2]21 CFR 182.10: Spices and other natural seasonings and flavorings generally recognized as safe (lists oregano, Lippia spp., and pot marjoram, Majorana onites). U.S. Food and Drug Administration (Electronic Code of Federal Regulations), 2026. guideline
- [3]Inhibition of enteric parasites by emulsified oil of oregano in vivo.. Phytother Res, 2000. open-label
- [4]Oregano extract ointment for wound healing: a randomized, double-blind, petrolatum-controlled study evaluating efficacy.. J Drugs Dermatol, 2011. RCT
- [5]Effects of Origanum onites on endothelial function and serum biochemical markers in hyperlipidaemic patients.. J Int Med Res, 2008. open-label
- [6]Safety and tolerability of carvacrol in healthy subjects: a phase I clinical study.. Drug Chem Toxicol, 2021. RCT
- [7]Effect of Origanum dubium, Origanum vulgare subsp. hirtum, and Lavandula angustifolia essential oils on lipid profiles and liver biomarkers in athletes.. Z Naturforsch C J Biosci, 2022. RCT
- [8]Labiatae allergy: systemic reactions due to ingestion of oregano and thyme.. Ann Allergy Asthma Immunol, 1996. observational
- [9]Carvacrol and human health: A comprehensive review.. Phytother Res, 2018. review
- [10]Possible therapeutic effect of carvacrol on asthmatic patients: A randomized, double blind, placebo-controlled, Phase II clinical trial.. Phytother Res, 2018. RCT
What changed
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Adversarial review pass: every evidence row re-read against its PubMed abstract. Official sources opened before citing: eCFR 21 CFR 182.20 (Origanum spp. essential oils/extractives GRAS) and 21 CFR 182.10 (oregano listed as Lippia spp.; pot marjoram as Majorana onites). No ODS fact sheet, NCCIH page or EMA monograph exists for oregano (NCCIH A–Z checked). Industry ties: none found; the wound trial is described as investigator-initiated, and the other studies list no funding or COI in PubMed (none in PMC). Retraction, expression-of-concern, erratum and withdrawn checks on all 8 PMIDs: none flagged. Page set indexable. Independent browser review (4 parallel reviewers, every evidence row checked against its abstract and official sources on the Vercel preview) found: no factual errors; carvacrol safety note now mentions the within-group lab shifts reported in the phase I abstract.