In this study, we investigated the pharmacological effect of humulus lupulus (hops) on gastric juice volume and acidity using a rat pylorus-ligated model. In an intraorally administered experiment, hops clearly increased gastric juice volume without affecting acidity. On the other hand, hops had no influence on gastric juice volume when it was intragastrically administered. A cholinergic agonist, carbachol, increased gastric juice volume without affecting acidity, whereas histamine increased gastric juice volume and acidity. The increase of gastric juice volume induced by carbachol was completely inhibited by atropine. On the other hand, atropine did not inhibit the increase in gastric juice volume induced by histamine. The increase in gastric juice volume induced by hops was completely inhibited by atropine. These results suggested that the increase in gastric juice volume induced by intraorally administered hops could be mediated by the cholinergic nervous system.