The pharmacokinetics and metabolism of radiolabelled salicylate were studied in rats and compared with that of the isolated perfused rat liver and the perfused rat kidney. Both parent compound and salicylate metabolites (mainly conjugates with glycine and glucuronic acid) were eliminated mostly into urine. The comparison of a relative proportion of metabolites eliminated in whole rats with that of the isolated perfused rat liver and the perfused rat kidney showed that both kidney and liver contributed to the salicylate metabolism. The glycine conjugate of salicylate was formed predominantly in the kidney whereas both kidney and liver participated in the formation of glucuronic acid derivatives.