1 SCH 28080 (2-methyl-8-(phenyl methoxy) imidazo-(1-2-a) pyrine-3-acetonitrile) is a novel drug unrelated to existing anti-ulcer agents. 2 The effect of placebo and increasing doses of the drug on gastric acid output and peptic activity was examined in four healthy men, in the resting state and following pentagastrin stimulation. 3 Significant inhibition of gastric acid secretion and peptic activity occurred with the 50 mg dose in both the stimulated and unstimulated states. Approximately 90% inhibition of acid output was achieved with the 200 mg dose. 4 Antisecretory activity of SCH 28080 is confirmed in man. This drug or an analogue may have potential in anti-ulcer therapy.