Melatonin improves abdominal pain in irritable bowel syndrome patients who have sleep disturbances: a randomised, double blind, placebo controlled study

Background and aims: Melatonin, a sleep promoting agent, is involved in the regulation of gastrointestinal motility and sensation. We aimed to determine if melatonin was effective in improving bowel symptoms and sleep disturbances in irritable bowel syndrome (IBS) patients with sleep disturbance. Methods: Forty IBS patients (aged 20–64 years; 24 female) with sleep disturbances were randomly assigned to receive either melatonin 3 mg (n = 20) or matching placebo (n = 20) at bedtime for two weeks. Immediately before and after the treatment, subjects completed bowel, sleep, and psychological questionnaires, and underwent rectal manometry and overnight polysomnography. Results: Compared with placebo, melatonin taken for two weeks significantly decreased mean abdominal pain score (2.35 v 0.70; p