Pentagastrin is a synthetic polypeptide that has effects like gastrin when given parenterally. It stimulates the secretion of gastric acid, pepsin, and intrinsic factor, and has been used as a diagnostic aid.

Pentagstrin's IUPAC chemical name is "L-Phenylalaninamide, N-((1,1-dimethylethoxy)carbonyl)-beta-alanyl-L-tryptophyl-L-methionyl-L-alpha-aspartyl".