(K.Schum.) Pierre ex Beille
Pausinystalia johimbe, (Rubiaceae), common name Yohimbe, is a plant species native to western and central Africa (Nigeria, Cabinda, Cameroon, Congo-Brazzaville, Gabon, Equatorial Guinea). Extracts from yohimbe have been used in traditional medicine in West Africa as an aphrodisiac and have been marketed in developed countries as dietary supplements.
Yohimbe is one of five Pausinystalia evergreen species growing in West and Central Africa in lowland forests. The tree grows about 30m tall, with a straight bole that is rarely larger that 50-60 cm in diameter. The bark is grey to reddish-brown, with longitudinal fissures, easy to peel and bitter-tasting. The inner bark is pinkish and fibrous. The sapwood is yellowish and the heartwood is ochre-yellow; the wood is fine-grained and relatively dense and moderately hard. The leaves grow in groups of three, with short (about 2 cm) stems. The blades are oval-shaped, 11-47 cm long and 5 - 17 cm wide. 
The main active ingredient in the extract is yohimbine. Yohimbe extract also contains other alkaloids with undefined properties, adding to concern about its safety. Among other alkaloids is corynanthine, an alpha-1 adrenergic receptor blocker and raubasine.
Extracts from the bark of yohimbe are used in West Africa as a general tonic and as an aphrodisiac. Yohimbe bark and extract are widely used in manufactured dietary supplements. The levels of yohimbine present in yohimbe bark and manufactured supplements are highly variable.
Yohimbe bark extract and yohimbine specifically have been declared as insufficiently characterized and possibly unsafe to consume by the European Union and US National Institutes of Health. The bark and extracts are banned from use in food and dietary supplements in many countries, including Great Britain, Ireland, Belgium, the Netherlands, Australia, New Zealand, Denmark, the Czech Republic, and Canada.