Treatment, beginning in November 1986, of chemotherapy with cisplatin (CDDP) was given to a 4-year-old girl with unresectable hepatoblastoma. Laparotomy for excision was performed after 16 months of therapy. The solution of CDDP was administered by dropping intravenously (DIV therapy) or intrahepatic arterially (IA therapy), and a suspension of crystalline CDDP with Lipiodol containing phosphatidylcholine was injected intrahepatic arterially (CDDP-suspension therapy). To evaluate the safety and effect of CDDP-suspension therapy in this case, toxicity and antitumor effect were investigated by comparison with DIV therapy. Under chemotherapy with CDDP, logarithm of alpha-fetoprotein reduced linearly. When a slope (k) of the regression line was defined as a constant of AFP reduction rate, k was -0.0072. AFP reduction rate under CDDP-suspension therapy (k = -0.0097, 12/1987-6/1988) was more rapid than that under DIV therapy (k = -0.0053, 2/1987-12/1987), and AFP reduced completely in June of 1988. The CDDP-suspension therapy may be suggestive of more effective treatment. Platinum (Pt) concentration in serum, urine and hepatic specimens was determined in order to investigate CDDP pharmacokinetics. The area under serum concentration (AUC) per doses and renal elimination rate were lower values under CDDP-suspension therapy. In the hepatic specimen, Pt concentration was significantly higher at the site where Lipiodol was localized. These results suggested that CDDP-suspension therapy delayed CDDP distribution and reduced toxicity. After CDDP-suspension therapy, reversible toxicity to the liver was observed. However, that to kidney or to blood components was less severe than after DIV therapy. After multiple DIV therapy, serum creatinine and blood urea nitrogen increased gradually in the course of therapy, while they tended to recovery after multiple CDDP-suspension therapy.