α-ethyltryptamine (αET, AET, "Monase"), also known as etryptamine, is a psychedelic, stimulant and entactogen of the tryptamine chemical class. This chemical is a kind of bulk pharmaceutical chemical. There are some basic informations about this crude drug: (1)CAS No.: ; (2)PubChem: CID 8367; (3)ChemSpider: 8064; (4)Synonym: 3-(2-aminobutyl)indole; (5)Formula: C₁₂H₁₆N₂; (6)Mol. mass: 188.27 g/mol.

αET is structurally and pharmacologically related to α-methyltryptamine (αMT), but its effects are slightly different. In contrast to αMT, αET is less stimulating and hallucinogenic, its effects resembling more those of entactogens like M ("Ecstasy").

Similarly to MDMA, αET has been demonstrated to be a releasing agent of serotonin, norepinephrine and dopamine (with serotonin being the primary neurotransmitter affected); in addition, it acts as a non-selective serotonin receptor agonist. Scientific research has shown that alpha-ethyltryptamine is a serotonergic neurotoxin.