Ceruletide (INN), also known as cerulein or caerulein, is a ten amino acid oligopeptide that stimulates smooth muscle and increases digestive secretions.

It stimulates gastric, biliary, and pancreatic secretion; and certain smooth muscle.

It is used in paralytic ileus and as diagnostic aid in pancreatic malfunction.

Ceruletide was discovered and its structure elucidated in 1967 by Australian and Italian scientists from dried skins of the Australian green tree frog (Ranoidea caerulea, formerly Hyla caerulea).

Surface ICAM-1 in turn promotes neutrophil adhesion onto acinar cells enhancing pancreatic inflammation.