The absorption of Urogastrone, glycoprotein with gastric antisecretory activity, from the rat intestine was studied using the Shild technique, in which the indirect assay of its appearance in the blood stream was facilitated by a concomitant lowering of gastric acid secretion. The intravenous or intraperitoneal administration of Urogastrone produced 40% inhibition of control levels of H⁺ output. In the intrajejunal administration, it caused only a little inhibitory response. However, when Urogastrone was administered intrajejunally with various bile salts or oil-in-water emulsions, strong inhibitory response of gastric H⁺ secretion was elicited. Trioctanoin emulsion was most effective on the activity of intrajejunally administered Urogastrone followed by olive oil, diethyl phthalate and liquid paraffin, respectively. The results suggested that orally active dosage forms for poorly absorbable macromolecules such as Urogastrone might be prepared by pharmaceutical modification.