AbstractThis review concerns the pharmacology of the serotonergic systems in the CNS. After the description of the anatomy of the serotonergic system the synthesis, release and inactivation of the neurotransmitter 5‐HT is delineated. From the different serotonergic receptors (5‐HT1A, 5‐HT1B, 5‐HT1C, 5‐HT1D, 5‐HT2and 5‐HT3) the current status with regard to available ligands, second messenger systems and physiological roles has been outlined. The last part of the review extends the relationship between the 5‐HT and other neurotransmitter systems in the CNS (e.g. dopamine, noradrenaline, substance P, glutamate, acetylcholine a