alpha-Ethyltryptamine (Monase) is both an inhibitor of monoamine oxidase and a monoamine releasing agent. To determine whether alpha-ethyltryptamine induces serotonergic deficits similar to that of other monoamine releasing agents such as 3,4-methyl-enedioxymethamphetamine (MDMA) and para-chloroamphetamine (PCA), rats were given multiple doses (8 x 30 mg/kg s.c.) of alpha-ethyltryptamine acetate. Serotonin and 5-hydroxyindole acetic acid (5-HIAA) levels and the number of 5-HT uptake sites (determined from [3H]paroxetine binding) were significantly decreased in frontal cortex samples at one week killing. A significant decrease in 5-HT and 5-HIAA levels was also observed in rat hippocampal samples. The results provide evidence that alpha-ethyltryptamine may induce serotonin neurotoxicity similar to that of MDMA and PCA.