Irritable bowel syndrome (IBS) is defined as abdominal pain and discomfort with altered bowel habits in the absence of any organic disorder. More than 10% of general population are considered to be affected by IBS. A guideline on its diagnosis and treatment has been issued in Japan in 2002. Accordingly, the therapeutic approach of IBS will be reviewed here. The most important issue of treatment is the establishment of a good physician-patient relationship. Given the limited efficacy of pharmacologic therapy and known psychological factors involved, effective treatment of IBS requires a comprehensive, multifaceted approach.