Dianhydrogalactitol was given to 28 patients with a variety of advanced solid tumors on a weekly schedule in iv doses ranging from 2 to 80 mg/m2. No significant toxicity was encountered at doses up to 40 mg/m2/week for 4 weeks. At higher doses mild-to-moderate nausea and vomiting and hematologic toxicity were noted. Thrombocytopenia was more common than granulocytopenia and frequently resolved more slowly. No adverse drug-realted effects on liver, renal, coagulation, or cardiac function were seen. Although no patient had significant antitumor response (as strictly defined), objective improvement was noted in two patients, one with hypernephroma and the other with malignant melanoma. for phase II studies, a weekly dose of 70 mg/m2 is recommended for patients with normal hematopoiesis, with reduction by 25% (55 mg/m2) in patients with extensive prior radiation therapy, prior chemotherapy, and/or widespread metastasis to the bone.