Oregano oil is a potent essential oil that contains an antibacterial compound called carvacrol, which some studies have shown to be as effective as standard antibiotics in fighting certain kinds of infections — including those caused by drug-resistant bacteria. A 2014 study, published in the Journal of Applied Microbiology, found medicinal-grade oregano oil effectively fends off murine norovirus in humans. (Some poultry farmers have even begun using oregano oil in place of standard antibiotics to reduce antibiotic resistance in poultry.)
Yet just because oregano oil is a plant compound doesn’t mean you can take it casually. Its potency is a good reason to use it — but cautiously, says Mindy Green, RA, RH, an essential-oils expert in Boulder, Colo.
Extended or high-dose use can stress the liver, which metabolizes essential-oil constituents, including carvacrol. And some healthcare providers warn that oregano oil could reduce microbial diversity in the gut.
Green recommends taking the oil in capsules because of its strong flavor, but you can also take the oil directly by mixing two drops in a teaspoon of carrier oil, such as olive oil. Oregano oil can irritate mucous membranes of the throat, esophagus, and stomach, so it should never be taken with just water; a carrier oil helps mitigate these effects. She suggests just 50 to 80 milligrams (two or three drops) per dose. Stick to formulas with at least 80 percent carvacrol, and take only those that are clearly labeled for medicinal use.
Green also cautions against using oregano oil for longer than one week. Take one dose three times a day for the first two days, she suggests. Then use one capsule twice a day. If you get no relief from your symptoms after seven days, discontinue its use and find another remedy.
“Some people take oregano oil daily for prevention, but I would never recommend that,” says Green. Instead, she suggests relying on immune-building herbal teas, such as echinacea and thyme, daily throughout the cold and flu season.
This originally appeared as “Is oregano oil really helpful for fighting colds? And is it possible to take too much?” in the April 2018 print issue of Experience Life.