Oil of Oregano: Uses, Capsules vs Liquid, and How to Dilute It

Never swallow undiluted oregano essential oil or put it near your eyes, nose or mouth. Avoid oregano oil supplements if you are pregnant or breastfeeding, take blood thinners, are having surgery in the next two weeks, or are allergic to mint-family plants. Ask your doctor first if you take diabetes medicine.

What is oil of oregano?

Oil of oregano is the volatile oil distilled from the leaves and flowers of oregano, most often wild Mediterranean oregano, Origanum vulgare, a member of the mint family (Lamiaceae). The same oil is searched for in many languages: "aceite de orégano" in Spanish, "origano ulje" in Croatian and Serbian.

Its character comes mainly from carvacrol, the oil's predominant compound, followed by its close chemical cousin thymol (Restorative Medicine oregano monograph). Both show antimicrobial activity in test tubes.

You will see the name used for two different kinds of product, and the difference matters:

• Oil of oregano supplements: softgels or liquid drops in which a measured amount of oregano oil is already mixed into a carrier oil, usually olive oil, and labeled for taking by mouth.
• Oregano essential oil: the pure, undiluted oil sold for aromatherapy and making your own topical blends. It is not made or labeled to be swallowed, and it is too strong to put on skin straight.

What is oregano oil used for? (¿Para qué sirve el aceite de orégano?)

People traditionally use oil of oregano in a few main ways:

• Colds and sore throats, taken at the first sign of symptoms.
• Digestion, including bloating and gut complaints.
• Skin, diluted and applied to spots, nail fungus or minor skin complaints.

Here is what the research actually shows. In the lab, carvacrol and thymol damage many kinds of bacteria and fungi. In animals, results are mixed: in a mouse study of staph infection, carvacrol alone delayed death but did not cure the mice (Restorative Medicine monograph). Lab and animal results often do not carry over to people.

Human evidence is thin. The study most often quoted gave 600 mg a day of emulsified oregano oil for six weeks to 14 adults whose stool tests showed intestinal parasites. Some parasites cleared and gut symptoms improved in 7 of 11 people with Blastocystis hominis (Force, Sparks and Ronzio, Phytotherapy Research, 2000). It had no placebo group and only 14 people, so it cannot show the oil caused the change. The Natural Medicines database, summarized on RxList, rates oregano as having "insufficient evidence" for uses including cough, acne, asthma and high cholesterol.

The honest summary: oregano oil is studied for antimicrobial effects and has a long folk history, but it has not been shown to prevent or treat colds, infections or any other illness in people. It should not replace antibiotics or antifungals your doctor prescribes.

Oregano oil capsules vs liquid drops

Most people choose between softgels (often called capsules, or "cápsulas de orégano") and liquid drops. Both contain oregano oil diluted in a carrier oil. The difference is mostly about taste, convenience and how precisely you can measure.

Some softgels are enteric coated, meaning the coating is designed to release the contents in the intestine instead of the stomach.

What the carvacrol number on the label means

Because carvacrol is the main active compound, many brands list it. You will see it written two ways:

• As a percentage of the oregano oil. Now Foods oregano oil softgels, for example, contain 181 mg of oregano oil per softgel, standardized to a minimum of 55% carvacrol.
• As milligrams per serving. Nature's Answer liquid lists a 50 mg blend of olive oil and oregano oil per serving, standardized to 7 mg of carvacrol.

A higher carvacrol figure means a stronger oil, not proven better results; no human studies compare carvacrol levels. Follow the label dose.

How to dilute oregano oil (aceite de orégano y coco)

Pure oregano essential oil is one of the harshest essential oils. Tisserand and Young's Essential Oil Safety, the standard aromatherapy safety reference, rates it a moderate risk for skin sensitization and mucous membrane irritation and recommends a maximum of 1.1% on skin. RxList sets a similar ceiling of 1% for oil applied to skin.

To make a roughly 1% blend at home, such as the popular "aceite de orégano y coco" (oregano oil in coconut oil):

1. Measure 1 fluid ounce (2 tablespoons, about 30 mL) of carrier oil. Virgin coconut oil, olive oil and jojoba all work. Coconut oil firms up when cool, which makes a balm.
2. Add about 5 to 6 drops of oregano essential oil. One milliliter is roughly 20 drops, so 30 mL of carrier needs about 0.3 mL (about 6 drops) for 1%. Droppers vary, so start at the low end.
3. Stir or shake well, label the jar, and store it away from heat and light.
4. Patch test on your inner arm and wait 24 hours before wider use. Stop if you get redness, burning or itching.

This homemade blend is for skin only. Do not drink it, and do not use it in the nose, mouth, eyes or other mucous membranes. If you want to take oregano oil by mouth, use a supplement that is made and labeled for internal use, where the manufacturer has already set the dilution. For more on carrier oils, see our guide to cold-pressed oils.

Mexican oregano vs Mediterranean oregano

In Mexican and Central American kitchens, "orégano" usually means a different plant. Mexican oregano, Lippia graveolens, belongs to the verbena family (Verbenaceae), not the mint family. Its oil is dominated by thymol (about 40 to 60%), with less carvacrol (about 3 to 25%) (PROSEA, Plant Resources of South-East Asia).

A bag of Mexican oregano is a fine kitchen spice, but it is not the plant used in most oil of oregano supplements.

Oregano oil safety and side effects

Sprinkling oregano on food is not a concern for most people. Concentrated oil is another matter, and the points below summarize RxList's Natural Medicines review unless another source is named:

• Burns and irritation. Undiluted essential oil can irritate or burn skin and mucous membranes. Always dilute it for skin, and never swallow it straight.
• Stomach upset is the most common mild side effect of supplements.
• Pregnancy and breastfeeding. RxList flags medicinal doses of oregano as a possible miscarriage risk and advises against them in pregnancy, and Tisserand and Young list the essential oil as contraindicated in pregnancy and breastfeeding. Now Foods and Nature's Answer both say not to use their products if pregnant or nursing.
• Bleeding. Concentrated oregano could make bleeding more likely, a bigger worry for anyone on warfarin, heparin, aspirin or similar drugs. Plan to stop taking it two weeks or more before an operation.
• Blood sugar. Large amounts may nudge blood sugar down. If you manage diabetes with medicine, talk to your doctor before adding it.
• Allergy. Oregano belongs to the mint family, so a known reaction to basil, sage, thyme or mint is a reason for caution.
• Keep it short. The only clinical study ran six weeks. There is no research on long-term daily use, so use it for short periods.

Keep it away from children unless a pediatrician says otherwise; Now Foods labels its softgels for adults only.

Find it at William's

We carry oregano oil in both of the main forms, so you can choose by taste and convenience:

• Nature's Answer oil of oregano liquid, 1 oz: alcohol-free drops in extra virgin olive oil, for people who want to adjust the amount.
• Now oregano oil enteric softgels, 90: 181 mg of oregano oil per softgel with at least 55% carvacrol, enteric coated to release in the intestine.
• Solaray oil of oregano 150 mg softgels, 60: 150 mg of oregano extract per softgel in an olive oil base.
• North American Herb & Spice Oreganol P73 softgels, 60 (Oreganol is that company's brand name): wild Mediterranean oregano oil in organic extra virgin olive oil.

We don't currently list pure oregano essential oil or dried Mexican oregano online; call the store to check what's on the shelf. If you are exploring other concentrated plant oils, our guides to black seed oil and coriander oil cover how they compare.

Frequently Asked Questions