Credit: Grant Cornett

Try it when: You have a tension headache.

How it works: Peppermint contains menthol, a natural anesthetic that dulls pain receptors. In fact, one study found that applying a peppermint-oil blend to the forehead was just as effective for pain relief as taking acetaminophen. However, peppermint oil can cause irritation if applied directly to the skin, so dilute it first. Add 2 drops to 1 teaspoon of a carrier oil (an unscented base oil, such as sweet almond), then massage into skin.

Good to know: Studies show that consuming peppermint oil may help alleviate stomach discomfort. Take ½ teaspoon, or try a coated tablet (available at drugstores).