A retrospective pharmacokinetic analysis was done of papaverine plasma level data in man reported in the literature. Upon i.v. administration the plasma level vs time curve can best be described by an open two-compartment model, and upon p.o. administration by open-compartment model. The biological half-life of papaverine varies between 1.5 and 2.2 hours, and has a volume of distribution of approximately 15% of the body weight. Papaverine is practically completely metabolized and underlies the first-pass effect upon p.o. administration.