The pharmacokinetics of metoclopramide have been studied in nine children receiving the drug as prophylaxis for cytotoxic induced vomiting. Plasma concentrations of metoclopramide have also been studied in three children with dystonic reactions to the drug. The pharmacokinetics in children were similar to those reported in healthy adults. There was no difference in the plasma concentration of metoclopramide of children with dystonia when compared to those without this adverse effect. Kinetic differences in childhood do not explain the occurrence of dystonia, which in the individual appears to be related to factors other than plasma drug concentrations.