Effect of acute and chronic treatment with nicotine hydrogen tartrate (NHT), on gastric secretion, was assessed in intact and vagotomized rats bearing permanent gastric fistulas. Intravenous infusion of NHT for 24 h with simultaneous collection of gastric juice demonstrated the inhibitory action of this drug on basal secretion and secretion stimulated with histamine, pentagastrin, and bethanechol chloride. Inhibition affected output of HC1 and pepsin and concentration of HC1. In nonstimulated and in bethanechol-stimulated rats, NHT also decreased the concentration of pepsin. Chronic treatment of rats with NHT also induced the inhibition of gastric secretion under various stimulation conditions. Inhibitory action of NHT on gastric secretion was also observed in vagotomized rats stimulated by secretagogues used in this study.