2-(p-methylallylaminophenyl) propionic acid, alminoprofene (INN), a new antalgic drug, was administered orally to men as a single (300 mg) and multiple doses (300 mg three times daily). Plasma and urine concentrations of alminoprofene were determined by gas-liquid chromatography. After the single oral dose, the peak plasma level (36.2 to 41.5 mg/l) was reached within 0.5 -1.5 h. the biological half-life ranged from 2.5 to 3.2 h. During chronic administration of alminoprofene, steady-state equilibrium was established within 24 h. The urinary excretion of alminoprofene as unchanged product and as glucuronide was very important.