Irritable bowel syndrome (IBS) is a chronic, relapsing condition characterized by the presence of abdominal pain and disturbed bowel habit. Symptoms of chronic constipation frequently resemble those of constipation-predominant IBS. Tegaserod (4 or 12 mg/day for 12 weeks), a drug that stimulates smooth muscle in the gastrointestinal tract, produces some benefit over placebo when used to treat IBS where constipation is a major symptom. Patients taking tegaserod reported an overall improvement in their IBS symptoms, an increase in number of bowel movements per day and a reduction in number of days without bowel movements. It is not clear if tegaserod improves symptoms such as abdominal pain, bloating, stool consistency and straining. When used to treat chronic constipation, the frequency of bowel movements increased with tegaserod, but increases over those seen with placebo were small. Diarrhea occurred more often among individuals taking high dose tegaserod (12 mg/day). Further studies are needed to assess the effect of tegaserod on quality of life. More information is needed on its effectiveness in men, as most of the studies involved women.