The central nervous system has the capacity to enhance the activity of dysfunctional penile tissue in men with erectile dysfunction (ED). Phase III clinical trials have been conducted using Apomorphine SL (TAP Pharmaceuticals, Deerfield, IL) as a centrally acting treatment for ED. Apomorphine SL has been administered to over 3000 men in over 75,000 doses. In three phase III crossover double blind studies 854 patients were given a total of 8263 tablets of apomorphine SL in 2 and 4 mg doses. The patients were between 18 and 70 years old and had multiple co-morbid conditions. Outcome measures included intercourse rates and erection rates on a per attempt basis as well as psychometric instruments and partner response evaluations. The results show that 74.1% of patients had moderate or severe grades of ED on inclusion into the studies, 31% had hypertension, 16% had documented coronary artery disease, 16% had dyslipidemia, and 16% had diabetes. Erections occurred rapidly (10–25 min). In 54.4% of attempts at 4 mg (vs 33.8% placebo, P < 0.001) erections suitable for intercourse were documented. A majority of the attempts at intercourse (50.6%, P < 0.001) were successful at 4 mg – a doubling of baseline rates. Mild nausea was the most common but infrequent side effect and the rare occurrence of syncope was the most significant. No cardiac deaths were attributed. It is concluded that the clinical trials of apomorphine SL demonstrate a safe and significant rate of restoration of erectile function by means of a central mode of action. Efficacy has been shown in men with cardiovascular disease and severe grades of ED.