My mother tried oregano with my father. He had jock itch and athlete's foot his whole life.
His oregano however was in regular dried herb form, not drops. Three weeks after starting, he started bleeding from his anus and he ended up in the hospital for three days. No one directly could attribute it to the oregano but it was the only thing he had changed in his diet and for the past four years he hasn't had another occurence(of course he hasn't taken oregano again).
I would some research first!
Director of Customer Care