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.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.