IN 1962, Friedhoff and Van Winkle reported the detection of 3,4-dimethoxyphenethylamine (DMPEA) in the urine of schizophrenic patients but not in that of normal individuals1. Attempts to confirm these findings have led to conflicting results. Two independent groups have verified that DMPEA is indeed produced by a high percentage of mental patients2,3, but another has also found it in the urine of control subjects as well4; yet others have been unable to detect it in either5,6. A recent report7 has presented a convincing correlation between the appearance of the ``pink spot'' equated with urinary DMPEA. and the diagnosis of schizophrenia. The interest in this specific base stems both from its close structural kinship to mescaline, a well established psychotogen, and from its implication in the metabolic chemistry of the endogenous catecholamines. 3,4 -Dihydroxyphenethylamine (dopamine) serves, in normal metabolism, as the precursor of noradrenaline and epinephrine, but it has been argued that an abnormal methylation might occur preferentially in psychotics. This specific conversion, yielding DMPEA, has been shown in vivo2,8. Alteration of dopamine metabolism has been observed in schizophrenic patients9 and this has been associated with abnormal transmethylation10. An important question has not been answered; is DMPEA a psychotomimetic agent in normal human subjects?