Linaclotide is a medication used to treat chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C) in adults. It works by activating guanylate cyclase‑C receptors on the lining of the intestine, which increases fluid secretion and speeds up bowel movements. Taken orally as a capsule once daily on an empty stomach, common side effects include diarrhea, abdominal pain, and gas.