The incidence of N-methyltransferase in blood samples from eleven normal controls, seven acute schizophrenics and eighteen chronic schizophrenics with acute episodes was investigated . The presence of the enzyme was determined by a simple, but highly sensitive, method using two-dimensional thin-layer chromatography and o~phthaladehyde spray reagent . Serotonine (5-HT) and 5~methoxytryptamine (5-OMeT) were used as substrates. The normal samples did not show any bufotenin spots when 5-HT was used as the substrate or 5-methoxy-N,N-dimethyltryptamine (5-OMeDMT) spots with 5-OMeT as the substrate . Of the seven eanples from the acute schizophrenics, six showed spots isographic with bufotenin or 5-OMeDMT, and thirteen of the eighteen samples from the chronic schizophrenics were positive for bufotenin or 5-OMeDMT .