Erectile dysfunction is a problem of male aging. Many of the men concerned use drugs or alternative preparations for improvement of their sexual activity. This article is a review of synthetic compounds, natural substances and plants with a confirmed effect on sexual functions in men. Inhibitors of phosphodiesterases, compounds acting on structures in the central nervous system, medicinal plants and some nutraceuticals improving erection are discussed. The mechanism of their action at the cellular level and also in the whole organism is described; their interactions with some common drugs are mentioned as well.