There are three major symptoms that may result. These are abdominal pain, abdominal swelling or bloating, and disturbance of bowel habit (either constipation or diarrhoea, or both). Other symptoms which may be experienced include: nausea, vomiting, indigestion, heart-burn, abdominal cramps, and low back pain. In addition IBS often leads to feelings of anxiety and depression which, in turn, may further increase the physical symptoms.

The cause of IBS is at present not known, and so treatment is aimed at relieving the symptoms. Sufferers may respond to antispasmodic drugs, laxatives, bulking agents, or anti-diarrhoeal drugs. In addition, clinical studies carried out by Dr. P. J. Whorwell at the University of South Manchester since 1984 have indicated that the symptoms of severe, persistent IBS can either be eliminated or substantially reduced by a procedure known as "gut-directed hypnosis". His results over the years have shown that, following this treatment, eight out of ten patients report that they feel 80% better.

Following this research, Elizabeth Taylor (a former colleague of Dr. Whorwell) set-up a register of approved hypnotherapists who are trained in the techniques of gut-directed hypnosis. Nigel Sprent trained in gut-directed hypnotherapy with Elizabeth Taylor in 1995, and was a member of the Register of Approved Gastrointestinal Psychotherapists and Hypnotherapists until 2003 when he started practising independently.