A procedure utilizing high pressure liquid chromatography coupled with UV detection is described for the determination of blood concentration of higenamine. Deproteinized serum was pretreated with C18 (Sep-pak C18 cartridge) and the 70% EtOH eluent was applied onto a reversed-phase column (μ Bondapak C18) with a 15% acetonitrile in 0.05 N NaH2 PO4-trichloroacetic acid mixed buffer (pH 2.8) as a mobile phase. With the UV detection at 232 nm, the retention times of higenamine and 1,2,3,4-tetrahydropapaveroline, an internal standard, were 5.2 min and 3.9 min respectively. The blood concentration of higenamine was measured at regular intervals afteri.v. injection of higenamine to rabbit. A drastic decrease in higenamine concentration to 30% of the maximum value obtained immediately after the injection, was observed during the first 1–2 min period and thereafter the rate of decrease was slowed down. The analytical result seemed to coincide with the pharmacological effect of higenamine exerting the maximum chronotropic and hypotensive effect at the completion of the injections which were progressively recovered.