Tegaserod (3‐(5‐methoxy‐1H‐indol‐3ylmethylene)‐N‐pentyl‐carbazimidamide), an aminoguanidine indole derivative of serotonin, is a selective partial agonist highly selective for 5‐HT4 receptor with an affinity constant in the nanomolar range. Tegaserod, by acting as an agonist at neuronal 5-HT4 receptors, triggers the release of further neurotransmitters such as calcitonin gene-related peptide from sensory neurons. The activation of 5-HT4 receptors in the gastrointestinal tract stimulates the peristaltic reflex and intestinal secretion, as well as inhibits visceral sensitivity. In vivo studies showed that tegaserod enhanced basal motor activity and normalized impaired motility throughout the gastrointestinal tract. Zelnorm® (tegaserod maleate) is indicated for the short-term treatment of women with irritable bowel syndrome (IBS) whose primary bowel symptom is constipation. In addition Zelnorm® is indicated for the treatment of patients less than 65 years of age with chronic idiopathic constipation.