On August 23, 2004, the FDA approved Zelnorm (Novartis Pharmaceuticals, East Hanover, NJ) for the treatment of chronic idiopathic constipation in male and female patients younger than 65 years of age. This makes Zelnorm the first FDA-approved prescription medication for use in patients with chronic constipation. Other available agents are indicated only for use in patients with occasional constipation. The FDA's decision was based on efficacy and safety data from 2 of the largest and longest randomized, double-blind, placebo-controlled, multinational, phase 3 trials conducted in chronic constipation. The two 3- month trials included more than 2600 male and female patients. Compared with placebo, Zelnorm was found to significantly increase the frequency of complete spontaneous bowel movements and to provide relief of the symptoms of chronic constipation for which patients seek help most often, including straining, hard stool, sense of incomplete evacuation, infrequent defecation, bloating, and abdominal discomfort.