The pharmacokinetics of l-carnitine, a cardiovascular drug, were studied in adult male cardiology patients following i.v. infusion of dl-carnitine hydrochloride. L-Carnitine appears to distribute into a rapidly perfused and then a more slowly perfused body space following administration. The overall apparent distribution volume Vd (ss) is consistent with extracellular body water. Serum levels of l-carnitine, from 2 different dose levels were adequately described by a 2 compartment model. Of the administered dose 80% was recovered in 24 h post dose urine.