Oregano is an herb used to flavor foods. Oregano has olive-green leaves and purple flowers. It is closely related to other herbs, including mint, thyme, marjoram, and basil. Oregano contains chemicals that might help reduce cough. Oregano contains chemicals that might help reduce cough. Oregano also might help with digestion and with fighting against some bacteria and viruses. People use oregano for wound healing, parasite infections, and many other conditions, but there is no good scientific evidence to support these uses.