Peppermint oil

Peppermint (Mentha piperita), a popular flavoring for gum, toothpaste, and tea, is also used to soothe an upset stomach or to aid in digestion. Because it has a calming and numbing effect, it has been used to treat headaches, skin irritations, anxiety associated with depression, nausea, diarrhea, menstrual cramps, and flatulence. It is also an ingredient in chest rubs, used to treat symptoms of the common cold. In test tubes, peppermint kills some types of bacteria and viruses, suggesting it may have antibacterial and antiviral properties. A number of studies support the use of peppermint for indigestion and irritable bowel syndrome.