The pharmacokinetics of flumecinol (Zixoryn) a new hepatic enzyme inducer has been studied in four beagle dogs and six healthy volunteers. The beagle dogs and the volunteers received the drug orally in a dose of 40 mg/kg of body weight and of 100 mg single dose respectively. Flumecinol was extracted from plasma with diethyl ether and analysed by gas-liquid chromatography using a flame ionisation detector (FID). The pharmacokinetic parameters of flumecinol were determined by computer evaluation of the plasma concentration-time curves. The peak plasma concentrations were found to be 5.3 and 2.1 hours in dogs and humans, respectively. Flumecinol is eliminated from the plasma of dogs and humans with half-lives of 38.95 and 17.16 hours, corresponding to a clearance of 53.2 litres/hour and 94.0 litres/hour, respectively.