The authors studied the concentrations of plasma catecholamines in 23 acute schizophrenics, 28 healthy controls, 20 chronic schizophrenics, and 26 otherwise diagnosed psychiatric cases. Blood samples were taken from the consecutively admitted acute schizophrenics before the administration of antipsychotic drugs and catecholamines were assayed with a high performance liquid chromatography and electrochemical detector. Plasma adrenaline in the acute schizophrenics and the other psychiatric patients was significantly elevated in comparison with the healthy controls. There were no significant differences in the noradrenaline concentrations among the four groups. The plasma dopamine concentrations in the acute schizophrenics were also higher than those in the healthy controls. It is unlikely that physical exercise caused the elevation of dopamine in the acute schizophrenics. There was no significant correlation between plasma catecholamines and BPRS scores in the acute schizophrenics.