Nephrotoxicity of cisplatin can be ameliorated with intravenous (IV) hydration and forced diuresis with mannitol. Cisplatin has recently been used with hypertonic saline which allows administration of higher doses amounting to 40 mg/m2/d for 5 days, without significant nephrotoxicity. In this report we describe our experience with administration of cisplatin in a dose range of 30 to 40 mg/m2/d for 5 days, administered with IV hydration alone. Thirteen patients with recurrent carcinoma of the head and neck region were treated with high-dose cisplatin along with 5-fluorouracil (5-FU) used as a continuous infusion. Eight patients received a total of 21 courses of cisplatin with the higher dose range (40 mg/m2 for 5 days) and the remainder received 11 courses with the lower dose range. The renal toxicity was minimal but the myelo-suppression was intense, frequently requiring hospitalization for the treatment of infections associated with neutropenia. Furthermore, we encountered severe peripheral neuropathy in five patients, four of whom developed major difficulties with ambulation. Six patients achieved objective regression of their tumor, two had minor response, and five failed to respond to chemotherapy. The study was terminated because of serious nonrenal toxicity from the high-dose cisplatin. Based on our limited experience, we believe that IV hydration alone, without the use of hypertonic saline, allows administration of high-dose cisplatin without significant nephrotoxicity. However, cisplatin used in a dose schedule of 40 mg/m2 for 5 days for more than three courses resulted in a disabling form of peripheral neuropathy.