The menthol in peppermint oil also has a numbing effect that provides me relief from an upset tummy, menstrual cramps, and the occasional headache due to muscle tension. When I apply on my temples and back of the neck, only one scant drop is needed or else your eyes will begin to water and burn — I tend to just lightly touch the top of the oil with my pointer finger. When I apply it to my belly, I use one or two drops. If the heat becomes too intense, following up with a little coconut oil takes the burn away. I also keep Digest Zen ($31) with me at all times, a blend of peppermint, anise, and ginger. The licorice-like scent reminds me of Yogi Tea's Stomach Ease but in oil form.