Irritable bowel syndrome (IBS) is a complex and prevalent functional gastrointestinal disorder that is treated with limited effectiveness by standard medical care. Hypnosis treatment is, along with cognitive-behavioral therapy, the psychological therapy best researched as an intervention for IBS. Eleven studies, including 5 controlled studies, have assessed the therapeutic effects of hypnosis for IBS. Although this literature has significant limitations, such as small sample sizes and lack of parallel comparisons with other treatments, this body of research consistently shows hypnosis to have a substantial therapeutic impact on IBS, even for patients unresponsive to standard medical interventions. The median response rate to hypnosis treatment is 87%, bowel symptoms can generally be expected to improve by about half, psychological symptoms and life functioning improve after treatment, and therapeutic gains are well maintained for most patients for years after the end of treatment.