Cis-dichlorodiammineplatinum (CDDP) pharmacokinetics were evaluated in eighteen patients with cancer who received 80 mg/m2 CDDP as a 20 min infusion. One hour before, 10 of them had 20 mg/m2 frusemide. Fifteen blood samples and fifteen urine samples were collected over the 5 hours following the infusion of CDDP. Platinum was assayed by flameless atomic absorption. The data did not detect any difference between patients with or without frusemide for the following platinum parameters: plasma concentration, urinary concentration, cumulative urinary excretion, renal clearance. These results suggest that frusemide has no influence upon cisplatin (CDDP) pharmacokinetics and if it protects the kidneys, it is not via kinetic modifications.