To elucidate the role of the serotonin (5‐HT) 2A/2C receptors in 3,4‐methylenedioxymethamphetamine (MDMA)‐induced neurotoxicity, MDMA was administered to rats and the presence of the serotonin transporter (5‐HTT) was assessed at the protein level with immunohistochemistry (IHC), and the RNA level with a Northern blotting technique. d‐lysergic acid diethylamide (LSD) and MDL 11,939 were given in conjunction with MDMA in order to assess the importance of 5‐HT receptors in MDMA‐induced neurotoxicity. The hypothesis is that the MDMA + LSD‐treated animals should have more neurotoxicity as measured by loss of 5‐HTTs compared to the MDMA‐treated animals. Moreover, the loss of 5‐HTTs should be attenuated in animals given the combination of MDMA + MDL 11,939, as the latter drug is a selective 5‐HT 2A/2C antagonist. The results showed that MDMA‐induced neurotoxicity was dose dependently increased by LSD. Moreover, the drug MDL 11,939 attenuated MDMA‐induced neurotoxicity, suggesting that 5‐HT2A/2C receptors are involved in MDMA‐induced neurotoxicity.