Peppermint M. ×piperita essential oil is on the FDA Generally Recognized as Safe (GRAS) list [3].
Peppermint M. ×piperita essential oil does contain some constituents that can be toxic: menthol, menthone, piperitone, and thymol. Peppermint M. ×piperita oil has been known to cause allergic reactions in the mouth, neck, and throat. These reactions were noted when peppermint M. ×piperita oil was consumed in large doses. If you are pregnant or nursing, suffering from any medical condition or taking medication, consult a Registered Aromatherapist before use. Avoid your eyes and mucous membranes. Always dilute essential oils appropriately.
You can view ACHS’s guidance on essential oil safety and best practices by downloading our Aromatherapy Safety ebook by clicking here.
References:
[1] https://info.achs.edu/blog/all-about-peppermint