Can peppermint oil relieve indigestion or IBS symptoms?

In theory, “peppermint oil reduces abdominal pain by targeting specific pain receptors,” says Adrian Masclee, a professor of gastroenterology and hepatology at the Maastricht University Medical Center in the Netherlands. It also may act as a muscle relaxant, he points out.

Does it help manage indigestion?

Masclee is skeptical that peppermint oil helps people with indigestion, as one industry-funded study reported. That’s because the study used enteric-coated capsules, which don’t release the oil in the stomach, where indigestion strikes. “If you encapsulate the peppermint oil, it will only be released in the small bowel,” he explains.

But Masclee doesn’t recommend uncoated peppermint oil capsules.

“Because peppermint oil has a muscle-relaxing effect, it may reduce the tone of the sphincter between the stomach and esophagus,” he says. “That can cause reflux in some people.”

Can peppermint oil help people with irritable bowel syndrome?

A handful of randomized trials—most of them small, short, and sponsored by supplement makers—hint that enteric-coated peppermint oil may reduce pain and discomfort in people with irritable bowel syndrome.

Now the results of a larger trial are in.

Masclee and other scientists—some with ties to a peppermint oil company—randomly assigned 189 people with IBS to take 182 milligrams a day of enteric-coated peppermint oil or a placebo.

After eight weeks, pre-set targets for declines in abdominal pain and overall symptoms were no different. There was a hint that the peppermint oil might curb pain slightly, but a new study would have to confirm that finding.

The bottom line

Don’t expect peppermint oil to have a substantial impact on the symptoms of IBS.