any reaction you are going to get from oregano oil is going to be to something that should not be in you. i can assure you i have taken a lot of it and the only thing that i noticed was that my guts were starting to swell. it does make cell membranes more permeable. but i took a bunch and bathed in a ton of it to get that way. i still bathe in it. man, that stuff straightens out my skin.