Ceruletide is a synthetic analog of the natural hormone cholecystokinin (CCK). It is a decapeptide with the following sequence: cyclo(D-Asp-Tic-Phe-Ser-Leu-Hand-Ala-Lys-Thr-Nle-NH2).

Ceruletide has several pharmacological actions, including stimulation of the release of digestive enzymes from the pancreas, contraction of the gallbladder and sphincter of Oddi, and inhibition of gastric acid secretion. It is used in clinical medicine for diagnostic purposes to test the motor function of the biliary tract and to diagnose gastrointestinal motility disorders.

Ceruletide has also been investigated as a potential treatment for certain conditions such as pancreatitis, gallstones, and intestinal obstruction, but its use is limited due to its side effects, which include nausea, vomiting, abdominal cramps, and diarrhea.