A phase I study was carried out on a new water-soluble nitrosourea, 6-deoxy-3,5 di-O-methyl 6-(3 methyl-3-nitrosoureido)-alpha-D-glucofuranoside (EDMN, CGP 6809), given every 2 weeks. A total of 18 patients received doses of 1, 2, 3, and 3.75 g/m2 as a 2- to 5-h infusion. Toxicity principally involved nausea and vomiting, hepatotoxicity, and abdominal pain. There was no evidence of cumulative toxicity. The dose of 3.75 g/m2 was not exceeded because in a previous phase I study, 4.5 g/m2 every 6 weeks was not tolerated; the recommended dose for phase II studies is 3.75 g/m2 every 2 weeks.