Peppermint (Mentha piperita), a popular flavoring for gum, toothpaste, and tea, is also used to soothe an upset stomach or to aid digestion. It has a calming and numbing effect, and is often used to treat headaches, skin irritation, nausea, diarrhea, menstrual cramps, flatulence, and anxiety associated with depression. 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, fungi, and viruses, suggesting it may have antibacterial, antifungal, and antiviral properties. Menthol and methyl salicylate, the main ingredients in peppermint, have antispasmodic effects, with calming effects on the gastrointestinal tract. Several studies support the use of peppermint for indigestion and irritable bowel syndrome.
Peppermint calms the muscles of the stomach and improves the flow of bile, which the body uses to digest fats. As a result, food passes through the stomach more quickly. However, if your symptoms of indigestion are related to a condition called gastroesophageal reflux disease or GERD, you should not use peppermint (see "Precautions" section).
Peppermint relaxes the muscles that allow painful digestive gas to pass.
Irritable Bowel Syndrome (IBS)
Several studies have shown that enteric-coated peppermint capsules can help treat symptoms of IBS, including pain, bloating, gas, and diarrhea. (Enteric-coated capsules keep peppermint oil from being released in the stomach, which can cause heartburn and indigestion.) However, a few studies have shown no effect. One study examined 57 people with IBS who received either enteric-coated peppermint capsules or placebo twice a day for 4 weeks. Of the people who took peppermint, 75% had a significant reduction of IBS symptoms. Another study comparing enteric-coated peppermint oil capsules to placebo in children with IBS found that after 2 weeks, 75% of those treated had reduced symptoms. Finally, a more recent study conducted in Taiwan found that patients who took an enteric-coated peppermint oil formulation 3 to 4 times daily for 1 month had less abdominal distention, stool frequency, and flatulence than those who took a placebo. Nearly 80% of the patients who took peppermint also had alleviation of abdominal pain.