Datelliptium chloride, hydrochloride (SR 95 156B, NSC 626718X, DHE) was studied in a phase I trial of escalating doses given on a single 24-h continuous intravenous infusion schedule. Doses were escalated from 40 to 500 mg/m2 in 19 patients who received a total of 24 courses. Courses were repeated after a minimal interval of 3 weeks. Local venous toxicity occurred at low doses (less than or equal to 100 mg/m2) and was circumvented by the use of a central venous access for higher doses. Other clinical adverse events occurred (greater than or equal to 330 mg/m2), including moderate nausea and vomiting, mild diarrhea, dry mouth, neuropsychiatric manifestations, and fatigue. All of these side effects were reversible and none was dose-limiting. The dose-limiting toxicity was related to hepatic laboratory-test abnormalities in the form of reversible elevations of levels of serum bilirubin and liver enzymes at doses of greater than or equal to 330 mg/m2. The maximum tolerated dose for this schedule is 500 mg/m2. Hematologic toxicity was minimal and non-dose-limiting. Neither drug-related deaths nor objective complete or partial responses were observed. However, a minor response and a long-term disease stabilization were obtained.