The therapeutic objectives for irritable bowel syndrome (IBS) patients are to improve their functioning in society. Accordingly, recommended management is to develop a logical strategy including a positive diagnosis, consideration of the patient's agenda and emotional state, critical appraisal of the efficacies of various drugs and a graded therapeutic response. Unfortunately, none of the currently available drugs (e.g. antispasmodics, antidiarrheals, osmotics, cathartics, bulking agents, tranquilizers, sedatives) are globally effective in treating all IBS symptoms, and the advanced receptor-targeted drugs are not always successfully and safely marketed. Consequently, more than half of patients may seek complementary and alternative medicine (CAM) to treat the annoying bowel symptoms. Physicians have considered these CAM measures to have an ‘enhanced placebo effect’. For example, many herbal medicine and plant products are globally used to treat IBS, whereas their efficacies are often inconclusive because of small sample sizes, inadequate data analyses and lack of standardized preparations. Meta-analyses do not establish their true efficacy. Acupuncture has long been employed by patients themselves to treat functional gastrointestinal disorders with satisfactory response, but its effect on IBS does not seem to be promising. Peppermint oil, melatonin and clay-like materials are effective in treating some IBS symptoms, while their true pharmacology remains enigmatic. In conclusion, IBS treatment is usually tailored to the individual's manifestations, ranging from reassurance to psychotherapy. Apart from conventional medications, CAM may be considered individually as a supplement or alternative to treat IBS patients that is at least equal in effect to placebo if patients do not exhibit any intolerable or serious side effects.