The combination of 90 mg of peppermint oil plus 50 mg of caraway oil in enteric-coated capsules taken three times per day led to significant reduction in IBS symptoms in a double-blind trial.¹ In a similar trial, capsules that were not enteric-coated were as effective as enteric-coated capsules.² The same combination has compared favorably to the drug cisapride (Propulsid) in reducing symptoms of IBS.³ The purpose of enteric coating is to protect peppermint oil while it is passing through the acid environment of the stomach.

Whole peppermint leaf is often used either alone or in combination with other herbs to treat abdominal discomfort and mild cramping that accompany IBS. The combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in a double-blind trial.⁴

Some people with IBS may benefit from bulk-forming laxatives. Psyllium seeds (3.25 grams taken three times per day) have helped regulate normal bowel activity in some people with IBS.⁹ Psyllium has improved IBS symptoms in double-blind trials.^10,11

Melatonin plays a role in the regulation of gastrointestinal function and sensation. In a double-blind trial, people with irritable bowel syndrome and associated sleep disturbances received 3 mg of melatonin or a placebo at bedtime for two weeks. Compared with the placebo, melatonin significantly decreased the severity of abdominal pain, although it did not affect bloating, stool frequency, or sleep patterns.¹³ Melatonin was also effective in another double-blind trial.¹⁴

In the intestinal tract, peppermint oil reduces gas production, eases intestinal cramping, and soothes irritation.¹⁵ Peppermint oil has been reported to help relieve symptoms of IBS in two analyses of controlled trials.^16,17 Evidence supporting the use of peppermint oil has come from double-blind trials that typically have used enteric-coated capsules that supply 0.2–0.4 ml of peppermint oil taken two to three times per day.^{18,19,20,21,22} Some trials have found peppermint oil ineffective.^23,24 However, a pooled analysis (meta-analysis) of 9 randomized controlled trials (with a total of 726 patients) found that enteric-coated peppermint oil capsules are a safe and effective treatment for IBS.²⁵

The combination of 90 mg of peppermint oil plus 50 mg of caraway oil in enteric-coated capsules taken three times per day led to significant reduction in IBS symptoms in a double-blind trial.²⁶ In a similar trial, capsules that were not enteric-coated were as effective as enteric-coated capsules.²⁷ The same combination has compared favorably to the drug cisapride (Propulsid) in reducing symptoms of IBS.²⁸ The purpose of enteric coating is to protect peppermint oil while it is passing through the acid environment of the stomach.

Whole peppermint leaf is often used either alone or in combination with other herbs to treat abdominal discomfort and mild cramping that accompany IBS. The combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in a double-blind trial.²⁹

Whole peppermint leaf is often used either alone or in combination with other herbs to treat abdominal discomfort and mild cramping that accompany IBS. The combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in a double-blind trial.³⁰

In a preliminary study of people with irritable bowel syndrome who took an artichoke leaf extract daily for two months, 26% reported an improvement in symptoms.³² Because no placebo group was used in this study and because irritable bowel syndrome has a high rate of response to placebo, additional research is needed to confirm this report. The amount of artichoke leaf used in the study was 320 or 640 mg per day of a 1:5 standardized extract.

Chamomile’s essential oils have eased intestinal cramping and irritation in animals.³³ Chamomile is sometimes used by herbalists to relieve alternating bouts of diarrhea and constipation, though research has yet to investigate these effects. This herb is typically taken three times per day, between meals, in a tea form by dissolving 2–3 grams of powdered chamomile or by adding 3–5 ml of herbal extract tincture to hot water.

A preliminary trial investigated the effectiveness of grapefruit seed extract in people with eczema and symptoms of IBS.⁴³ Participants received either 2 drops of a 0.5% oral solution of grapefruit seed extract twice daily or 150 mg of encapsulated grapefruit seed extract three times daily. After a month, IBS symptoms had improved in 20% of those taking the liquid, while all of the patients taking capsules noted definite improvement of constipation, flatulence, abdominal discomfort, and night rest. These results need confirmation in double-blind trials.

Whole peppermint leaf is often used either alone or in combination with other herbs to treat abdominal discomfort and mild cramping that accompany IBS. The combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in a double-blind trial.⁴⁴