Bufotenin was found to be present in urine samples of schizophrenic patients and autistic children, but not of normal controls. The identification was based on TLC of the tertiary amine fraction using a specific o-phthalaldehyde spray, and also on GC. Unambiguous proof of the identity of bufotenin has now been provided by GC-MS ~~alysis of the bufotenin-positive samples through its trimethylsilyl derivative.