In ten healthy volunteers the plasma and urine concentrations of heptaminol (Heptylon) were determined by high-performance liquid chromatography after intravenous administration of 250 mg heptaminol and oral intake of 2 x 150 mg heptaminol in tablet form, and the pharmacokinetic parameters were calculated. Heptaminol was rapidly and entirely absorbed following oral administration of heptaminol. Mean plasma peak concentrations of 1.6 mg/l were reached after 1.8 h, the area under the plasma concentration-time curve was equal to that after intravenous administration. The dominant terminal plasma half-life was 2.5-2.7 h. The total clearance amounted to 700 ml/min, and nearly all the dose given was recovered unchanged in urine within 24 h, indicating renal elimination by glomerular filtration and tubular secretion without metabolization.