Six drug free chronic schizophrenic patients were placed on a rigorous diet. After the 4th wk of a drug holiday lasting about 13 wk, the urinary samples of the patients were analyzed for dimethylated tryptamines. All of the patients showed exacerbations of their symptoms during the drug free period. Bufotenine was identified for all 6 patients on silica gel G plate by 2 dimensional thin layer chromatography with o phthalaldehyde as the spray reagent. This identification was confirmed by gas chromatography and gas chromatography mass spectrometry on 2 pooled samples from each of 3 patients. The urine samples of 3 patients showed N,N dimethyltryptamine on cellulose plates with dimethylaminocinnamaldehyde as the spray reagent. The levels of N,N dimethyltryptamine were very low so at least 3 positive samples from the same patient were pooled and the identification of N,N dimethyltryptamine was confirmed by gas chromatography mass spectrometry. Both bufotenin and N,N dimethyltryptamine were quantitated in urine samples from all 6 patients by monitoring the base peak at m/e 58 of the trimethylsilyl derivatives. All 6 of the patients showed bufotenin and 3 of these showed N,N dimethyltryptamine.