4,5-Dihydroxytryptamine (4,5-DHT) is a serotonergic neurotoxin of the tryptamine family.

[1][2] It is structurally related to the monoamine neurotransmitter serotonin (5-hydroxytryptamine; 5-HT).

[1][2] The drug is also a monoamine reuptake inhibitor.

[3] Its analogue 4-hydroxy-5-methoxytryptamine (4-HO-5-MeO-T) is also a serotonergic neurotoxin.

[3] Rapid auto-oxidation of 4,5-DHT and 4-HO-5-MeO-T prevents them from being used as serotonergic neurotoxins in scientific research.