BACKGROUND: In childhood, cisplatin is an essential component of solid tumour therapy such as in neuroblastomas, germ cell tumours, bone tumours, liver tumours and brain tumours. The potential nephotoxicity of cisplatin is widely recognized, but little information is available on permanent sequelae. METHODS: Of the 500 children included in the Swiss Pediatric Oncology Group Late Effect Study, a group of 46 patients (27 males and 19 females) aged 5.7-28 years (median 14 years) surviving the above-mentioned solid tumours entered the present study. The patients were disease-free and off antineoplastic medication for at least 3 years. No recent gastrointestinal or urinary disturbances had occurred, and diets as well as appetites were normal. RESULTS: Blood pressure and plasma or urinary calcium and phosphate were similar in 17 patients treated with cisplatin (dose 142-717, median 400 mg/m2), in 19 patients without cisplatin and in 20 control subjects. A tendency (P<0.02) towards increased plasma creatinine (79 (69-89) micromol/l; median and interquartile range) and low plasma magnesium (0.80 (0.78-0.85) mmol/l) was noted in patients treated with cisplatin as compared with those without cisplatin (68 (58-80) micromol/l; 0.84 (0.79-0.90) mmol/l) and controls (71 (64 80) micromol/l; 0.83 (0.80-0.90) mmol/l). No correlation was noted between the dosage of cisplatin and circulating magnesium or creatinine. CONCLUSIONS: The study demonstrates that the permanent renal disturbances ((i) decreased renal function and (ii) hypomagnesaemia) noted after treatment with cisplatin during infancy or childhood are mild. Furthermore, the study does not demonstrate renal sequelae in patients with the same malignancies who had been treated without cisplatin.