Twelve randomised trials with 835 patients showed that peppermint oil is a safe and effective therapy for pain and IBS symptoms. It contains L-menthol, which produces antispasmodic effects on the gastrointestinal tract.
You can use peppermint oil as a dressing in salads or for cooking (1 tbsp per meal). Should you take an excessive dose, you could experience side-effects such as heartburn, so please check with your doctor if this happens.
You can prepare peppermint oil at home by putting crushed mint leaves in a jar, cover them with olive oil and let them soak for 2-3 days.