Thirty-nine patients received 600 mg/m2 OF MGBG intravenously every week for the treatment of advanced refractory ovarian cancer. Twenty-seven of these received adequate trials, and only two had partial remissions lasting 3 1/2 and 4 months each. Toxicity was substantial, with severe hematologic toxicity in 26%, diarrhea in 22% (severe in 7%), skin rash in 26% (severe in 7%), and vomiting in 70% (severe in 11%). Fatigue, facial paresthesias, and flushing during drug administration were frequent. It appears that MGBG in this dose and schedule has little activity against advanced ovarian cancer.