Also known as 5-hydroxytryptamine. An example of a neurotransmitter, it is a naturally occurring substance closely related to naturally occurring and synthetic hallucinogenic tryptamines.

4-Bromo-2,5-dimethoxy-amphetamine (also known as brolamphetamine) is a synthetic amphetamine-type compound under international control according to the 1971 UN Convention on Psychotropic Substances. It is one of the most potent hallucinogens being active at 1–3 mg oral doses. DOB is a selective agonist of serotonin receptor subtypes, especially 5-HT2A, in the brain, but is also a strong vasoconstrictor at the periphery.

As subtype of serotonin (5-hydroxytryptamine, 5-HT) receptors, 5-HT2A receptors are present in the brain and the periphery and bind the endogenous neurotransmitter 5-HT. Classical hallucinogens, such as LSD, psilocin or DOB, are agonists of 5-HT2A receptors in the central nervous system. In the periphery, 5-HT2A receptors are involved in various cardiovascular functions, platelet aggregation and nociception.