Peppermint Oil and Fiber

Ford and colleagues combined the results from 12 studies comparing fiber with placebo or no treatment, 22 studies comparing different antispasmodic drugs to placebo, and four studies examining treatment with peppermint oil.

Although there were fewer peppermint oil studies, the trials were well designed and all showed peppermint oil to be effective.

Other highlights of the analysis include:

• Based on the combined data, the researchers estimated that one in 2.5 patients would get significant relief of symptoms if treated with peppermint oil, compared to one in five patients taking antispasmodics and one in 11 patients taking fiber. Peppermint oil is sold in capsules, and the study participants took about 200 milligrams two or three times a day.
• Insoluble bran-based fibers were not very effective, but soluble psyllium-based fiber treatments like Metamucil were. When psyllium therapies were considered on their own, one in six treated patients had significant improvement in symptoms.
• When the 22 antispasmodic studies were combined, the drug scopolamine was among the most effective. The researchers recommend scopolamine, which is extracted from the corkwood tree, as the first-line antispasmodic treatment for IBS.

Ford and colleagues concluded that psyllium-fiber therapy is a good first-line treatment for constipation-predominant IBS, while peppermint oil and scopolamine are good choices for diarrhea-predominant IBS.

The analysis appears in the latest issue of BMJ Online First. In an accompanying editorial, Jones writes that the findings should reawaken interest in these treatments and spur research into their use for IBS.

"We really don't know which patients benefit most from which type of treatment," he tells WebMD.