In the intestinal tract, peppermint oil reduces gas production, eases intestinal cramping, and soothes irritation. In preliminary research, peppermint oil has also reduced spasms of intestinal musculature. 35 Caraway oil is believed to have similar effects to peppermint oil. A few studies have not found peppermint oil to be helpful. 36 or, in one case where peppermint oil increased symptoms, did not administer the oil by mouth.
Chamomile acts as a carminative as well as soothing and toning agent for the digestive tract.
Chamomile's essential oils have also eased intestinal cramping and irritation in animals. It is sometimes used by herbalists for those with IBS experiencing alternating bouts of diarrhea and constipation, though research has yet to investigate these effects. Some people with IBS may benefit from bulk-forming laxatives. 39 Psyllium has improved some symptoms of IBS in double blind trials. Refer to the individual herb for information about any side effects or interactions.