My great grandmother lived over a hundred and she loved herbs. Whenever she had an upset stomach from a cold or a stomach bug, she would drink a few drops of oregano essential oil mixed with sugar and water. I think it was her way of killing the stomach bugs naturally.
It's probably dangerous to do that nowadays, unless the oregano oil is very pure and non-toxic. I tried this remedy once and it was the worst thing I've ever tasted. I also mixed it with sugar, but it was still very strong and bitter. I had to have a glass of milk afterward.