Sildenafil has proven effective in the therapy of male erectile dysfunction. However, little is known about other potential beneficial effects of sildenafil. Meanwhile, first observations have been made in numerous medical disciplines and disorders. Small doses of sildenafil may be a useful adjunct to inhaled iloprost in the management of pulmonary hypertension. In female sexual dysfunction and infertility, genital blood flow and endometrial thickening are enhanced after application of the compound. In gastrointestinal disorders, sildenafil also exerts several effects which might be of clinical relevance. In patients with heart failure, endothelial dysfunction is influenced by the phosphodiesterase-5 (PDE 5) inhibitor and exercise capacity might be improved. Moreover, in the treatment of Raynaud's phenomenon, a disease without highly effective medical treatment option yet, first observations with sildenafil seem to be promising.