The safety and pharmacokinetics of vamicamide, a new anticholinergic drug, were examined in healthy male volunteers in single- and multiple-dose studies. In the single-dose study, 14 subjects were given one or two oral doses of vamicamide after fasting in a rising dose way; two subjects were given 0.7 mg, six subjects 1.5 and 6 mg, and remaining six subjects 3 and 12 mg. In the multiple-dose study, nine subjects were divided into two groups of six subjects for vamicamide treatment and three subjects for placebo treatment. The subjects from active and placebo groups were given, in a single blind way, an oral dose of 6 mg of vamicamide and placebo, respectively, three times daily for five days and once on day 6. Vamicamide was well tolerated by all subjects. Subjective symptoms of dry mouth were transiently observed in two and four subjects after single dosing with 6 and 12 mg of the drug, respectively, and in two subjects during multiple dosing with the drug. Vamicamide suppressed salivary secretion for six hours or longer after dosing. Dry mouth and suppressed salivary secretion were considered to be due to the anticholinergic effect of the drug. There were no abnormal findings in clinical laboratory tests, electrocardiograms or vital signs. The pharmacokinetics of vamicamide were linear. Serum concentrations of vamicamide peaked 1.9 hours after single dosing and declined with elimination half-life of 5.2 hours. The maximum concentration and area under the concentration-time curve increased in proportion to the dose. Serum concentrations reached steady state by day 3 during multiple dosing. Vamicamide was extensively excreted in the urine; more than 80% of the given dose was recovered unchanged in the urine. The renal clearance was 289 ml/min.