Oregano is a flowering herb that is available in more than 40 species, but the essential oil from Origanum vulgare is considered to possess the most medicinal benefit. Oregano contains naturally occurring substances called phenols, of which carvacrol and thymol are believed to be the ones that have powerful antiviral, antibacterial, antifungal, and antiparasitic properties. Oregano oil has been shown to be as effective at inhibiting the growth of certain bacteria as standard antibiotics, such as penicillin and streptomycin.
Oregano has also demonstrated activity against cancer cells in laboratory studies. A study conducted in India, for example, showed that oregano supplementation markedly inhibited the development of induced colon cancer in rats. (Srihari 2008) A study published in Nutrition and Cancer explored the impact of oregano extracts on cell proliferation and cell death in colon cancer cells. The researchers concluded that the whole extract, rather than specific components, can be responsible for the herb’s anticancer effects. (Savini 2009)
A recent study published in Phytomedicine investigated the anti-tumor abilities of carvacrol in human metastatic breast cancer cells. The researchers from India found clear evidence that carvacrol promoted apoptosis (cell death) in metastatic breast cancer cells in a laboratory setting. (Arunasree 2010)
No dose has been determined for the use of oregano in cancer. Oregano oil should not be taken internally unless it is diluted, and the length of treatment should be limited. Consult a healthcare provider before using oregano.
Arunasree KM. Anti-proliferative effects of carvacrol on a human metastatic breast cancer cell line, MDA-MB231. Phytomedicine 2010 Jul; 17(809):P 581-88
Srihari T et al. Role of oregano on bacterial enzymes in 1,2-dimethylhydrazine-induced experimental colon carcinogenesis. Can J Physiol Pharmacol 2008 Oct; 86(10): 667-74
Savini I et al. Origanum vulgare induces apoptosis in human colon cancer caco2 cells. Nutr Cancer 2009; 61(3): 381-89