Abstract Altogether 406 patients were included in five studies, and all patients were examined and controlled in the Oulu University Hospital during the years 1991–1998. Twenty-nine patients with mixed-type erectile dysfunction (ED) were recruited into a randomized, controlled, double-blind crossover comparison of placebo and high-dose yohimbine hydrochloride (36 mg per day orally). Positive clinical responses were obtained in 44% of the patients during yohimbine treatment and in 48% during placebo treatment. Thirty patients with ED underwent an intracavernosal injection test (ICI) using three different active agents (prostaglandin E1(PGE1), papaverine hydrochloride (PV), moxisylyte (MS)) and physiological saline. PGE1 produced significantly better rigidity than either PV or MS. Sixty-nine patients with ED who had started ICI therapy with PGE1 at least three years previously were invited to a control examination to find out the long-term outcome of this treatment and to evaluate the patients' overall satisfaction with their sexual life. 46.4% of the patients had discontinued PGE1 therapy, the mean time of using PGE1 having been 23.3 months (range 0–48 months). 34.8% of the patients reported that their own spontaneous erections had improved during the PGE1 therapy. The sexual functions of 155 patients with benign prostatic hyperplasia (BPH) were evaluated before TURP and 6 and 12 months afterwards with questionnaires. Only 26% of the patients had completely satisfactory erections before TURP, while 22% had satisfactory erections 6 months later and 24% 12 months later. The majority of patients (about 70%) were satisfied with their sexual life both before and after the procedure. 123 men with symptoms of andropause participated in a randomized, placebo-controlled study to assess the effects of dihydrotestosterone (DHT) gel in men with andropausal symptoms. The drug was administered transdermally once a day during six months. Early morning erections improved significantly (p < 0.003) in the DHT group by the three-month control, the ability to maintain erections was better, and there was also a positive effect on libido. In the patients with a elevated (> 12) international index of the prostatic symptoms score (I-PSS) before DHT treatment, I-PSS decreased from 17.7 to 12.3 points. As a conclusion yohimbine hydrochloride is no better than placebo in the treatment of patients with mixed-type ED. PGE1, PV and MS are well tolerated, and PGE1 was shown to be the most effective drug of the three. ICI therapy with PGE1 in long-term use is safe and effective. Sexual functions in men did not change after TURP, and this group of aging men were fairly satisfied with their sexual life despite of the fact that they had some ED and one third of the patients had not had intercourse during the previous year. Transdermal administration of DHT in aging men improves sexual function.