Cutaneous reactions and plasma histamine levels were evaluated in 30 adolescents subsequent to the administration of suxamethonium 1.5 mg kg−1or atracurium 0.6 mg kg−1. Plasma histamine levels were measured by the radio‐enzymatic assay using histamineN‐methyl transferase. In the atracurium group, the change in plasma histamine level was significant at the 2 min mark, but was not significant in the suxamethonium group. About 60% of the patients in each group developed a cutaneous reaction. Erythematous cutaneous reactions following atracurium were frequently associated with a mild increase in plasma histamine levels, whereas the rashes induced by suxamethonium in adolescents were not associated with changes in plasma hi