Yes, hypnotherapy works. Plenty of examples exist in the scientific literature showing the effectiveness of clinical hypnosis in various ailments, including anxiety, Irritable Bowel Syndrome (IBS), and pain. For example, a 2003 study had all its 204 participants with IBS go through 12 weekly hypnosis sessions, each lasting an hour. Seventy-five percent of the women and 58% of the men reported symptom relief immediately after completion of treatment. Over 80% of people in this group were still relieved up to six years later. Only 10% required further treatment after hypnosis.