A method is described for the purification of enterogastrone, an inhibitor of the secretion of gastric juice, from the extracts of the upper part of porcine small intestine. The starting material used was Tannate purified enterogastrone concentrate (Greengard and Grossman), which was subjected to column chromatography on Sephadex G-100 and eluted with 0.2M acetic acid. Turther purification of the active material from gel filtration was made by column chromatography on CM-cellulose. The purified enterogastrone so obtained showed inhibitory activity 200 times that of the fraction obtained by the first purification step.