In order to test the capability of a reinjection to improve an incomplete pharmaco induced erection, we submitted 30 impotent patients, with incomplete erectile responses to 10 mu g PGE1 + 1 mg phentolamine, to a second injection of 15 mu g PGE1 + 1.5 mg phentolamine + 30 mg papaverine, fifteen minutes after the first injection. Twenty-one patients improved their erection including nine who achieved complete rigidity. We conclude that incomplete pharmaco induced erections can frequently be improved by reinjection.