Does it work?

Peppermint (Mentha piperita) oil has been shown to have antispasmodic effects and may improve irritable bowel syndrome (IBS) symptoms such as cramping and bloating. Several clinical trials have used enteric-coated peppermint oil in IBS or recurrent abdominal pain in children. Significant improvements in symptoms of IBS were reported. However, more research is needed before a firm conclusion can be made.

Dangers and possible side effects.....

Heartburn might actually be a side effect of taking oral peppermint oil. Enteric-coated peppermint oil has been used in clinical studies for peptic ulcer and other stomach problems. Caution is advised when taking peppermint supplements, as adverse effects including heartburn, anal burning, and drug interactions are possible. Peppermint oil by mouth may increase blood levels of the drugs felodipine (Plendil®) and simvastatin (Zocor®). Peppermint oil increases levels of cyclosporine in the blood. Peppermint supplements should not be used if pregnant or breast feeding, unless otherwise directed by a doctor. Do not use peppermint oil in individuals with gallbladder problems.