Another possible oregano oil side effect is nausea. This is usually caused by thymol, a natural plant chemical found in oregano and other herbs. In high doses, it can be an irritant, which affects the internal organs. Avoid taking oil of oregano on an empty stomach, and discontinue its use if nausea persists.

This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.