Urinary excretion of salsolinol (6,7-dihydroxy-1-methyl-1,2,3,4-tetrahydroisoquinoline) in 30 male alcoholic patients during the withdrawal period was determined. They were divided into two groups, i.e., Group A with 14 subjects had a high level of urinary salsolinol (51.9 +/- 40.8 ng/mg creatinine) on admission to a hospital, and Group B with 16 subjects showed a low level of the substance (3.9 +/- 1.9 ng/mg creatinine). Following a sustained drinking bout, urinary salsolinol in Group A declined to a normal level within a few days. We found that the subjects in Group A showed a greater excretion of urinary dopamine and norepinephrine than those in Group B. There were no differences between the two groups in levels of blood ethanol, serum GOT, GPT and gamma-GTP.