Background Effective therapies for irritable bowel syndrome (IBS) are disappointing. Therefore, IBS patients have a growing interest for alternative medicines including osteopathy.

Aim We aimed to evaluate the effect of osteopathy on the severity of IBS in a randomized sham-controlled trial.

Methods We prospectively assigned 30 patients with IBS (23F, 7M, mean age 45.8±16.4 years) fulfilling the Rome III criteria in a 2/1 ratio to receive either osteopathy or sham osteopathy. Two separate sessions were performed at a 7-day interval (days 0 and 7) with a further 3 weeks of follow-up (day 28). The primary outcome included at least a 25% improvement in the IBS severity score at day 7. The secondary outcomes included the impact of IBS on quality of life, psychological factors, and bowel habits.

Results The severity of IBS decreased in both groups at days 7 and 28. At day 7, this decrease was significantly more marked in patients receiving osteopathy compared with those receiving the sham procedure (−32.2±29.1 vs. −9.0±16.0, mean difference normalized to the baseline P=0.01). This difference did not persist at day 28 (P=0.4). Both anxiety and depression scores decreased without difference between groups. Stool frequency and consistency were not significantly modified.

Conclusion Osteopathy improves the severity of IBS symptoms and its impact on quality of life. Osteopathy should therefore be considered for future research as an effective complementary alternative medicine in the management of IBS symptoms.