Elobixibat is a novel small-molecule that acts as an inhibitor of the ileal bile acid transporter (IBAT), and used for chronic constipation in Japan. Elobixibat selectively inhibited IBAT in vitro, and dose-dependently inhibited the absorption of bile acids in vivo. Also, elobixibat dose-dependently increased wet fecal weight in a rat loperamide-induced constipation model. The drug-drug interaction study suggested that elobixibat may have a clinically slight inhibitory effect on P-glycoprotein. In a phase II study with chronic constipation, the recommended dosage for oral administration of elobixibat once daily was estimated to be 10 mg. In a phase 3 study with chronic constipation, the superiority of the elobixibat 10 mg group to the placebo group was demonstrated in the change from baseline (ie, the last week of the 2-week run-in period) in the frequency of spontaneous bowel movements per week during the first week of treatment set as the primary endpoint. In a long-term study in which elobixibat was administered to patients with chronic constipation for 52 weeks, the ameliorating effects of elobixibat on constipation were observed from the first week of treatment and maintained well until week 52. In addition, the safety/tolerability of elobixibat administered once daily for 52 weeks was considered to be acceptable. Therefore, elobixibat has a mechanism of action that differs from any of the existing therapeutic agents for constipation and is expected to become one of the new treatment options for chronic constipation.