Peppermint has become one of the most-used oils in my stash. I initially started using it to make my water taste interesting, because anything to get me to drink more water is worth it, but I have found many other uses:
Breathing in peppermint is an effective way to kill coughy/sneezy junk quickly. Putting it on the back of the neck and on the hands is a good way to keep the fragrance close. I like to put my pepperminty hands over my nose and take a deep breath. Combine with lavender for an added boost.
Combine peppermint, lemon, and lavender together in a capsule for allergy relief.
(See the post on allergies for more details.)
Rubbing straight peppermint on the stomach area kills that queasy, nauseous feeling quickly. It burns a little bit, much like Icy Hot. Also, put a drop on your tongue or finger, and hold on the roof of your mouth for 10-20 seconds.
Put a drop in water or tea, and drink after an acidic meal. Put a drop on your tongue or finger, and hold on the roof of your mouth.
Also, rub a drop over your esophagus area or stomach or wherever you're feeling the burn.
Use by itself or with lavender. Put a drop on the back of your neck, and rub some on the temples. Don't get close to your eyes!
I have read about other uses, but these are the ones that I have experienced firsthand. More to come soon!