Although veno-occlusive dysfunction is a frequent cause of impotence, a definitive therapeutic strategy has not yet been clearly defined. A total of 56 patients with corporeal veno-occlusive dysfunction diagnosed by dynamic infusion cavernosometry-cavernosography (flow to maintain erection greater than 10 ml. per minute and rate of corporeal pressure decrease after interruption of intracavernous infusion greater than 50 mm. Hg for 30 seconds) not considered suitable candidates for surgery underwent self-injection therapy. A vasoactive mixture composed of 12.1 mg./ml. papaverine hydrochloride, 10.1 micrograms./ml. prostaglandin E1, 1.01 mg./ml. phentolamine mesylate and 0.15 mg./ml. atropine sulfate was used. After dose titration of the drug mixture 54 patients (95%) were able to obtain sustained rigid erections that guaranteed satisfactory sexual activity. Mean (plus or minus standard error of mean) volume of injected mixture was 0.42 +/- 0.09 ml. (range 0.25 to 0.90 ml.). Four patients (7%) reported transient hypotension that did not recur after the application of a penile rubber band before injection. At a mean followup of 16 months 6 patients (11%) discontinued use of injections, 37 (69%) were satisfied and using the mixture, and 11 (20%) maintained rigid erections using a lower than initial dose. No major complications were encountered. The association of drugs with different mechanisms of action caused a synergism that potentiated the therapeutic activity and reduced side effects by decreasing the total drug dose.