Mucuna pruriens, also known as velvet bean, is an annual shrub that grows long vines. This climbing shrub is found in tropical areas, such as the Caribbean, India, and Africa. It has many common names, including cowhage, picapica, and cowitch. The name "velvet bean" is derived from the fact that the plant is covered in soft hairs when young. As the velvet bean matures, however, it loses these hairs.
The leaves of the velvet bean are ovate or rhombus-shaped, with sharp points and grooved sides. When the plant is young, both sides of the leaves are almost completely covered in fuzzy hairs. The leaves are around 0.1 inch (0.2 cm) long. Multiple leaves can grow on one stem, with each stem growing up to 0.2 inches (0.5 cm) long.
Velvet beans are flowering plants. Each flower head can blossom into just a few or an abundance of flowers. These flowers can be white, dark purple, or light purple. Loose hairs cover the seed pods of these flowers, often causing severe irritation of the skin when contact is made. After the flowers have bloomed, the velvet bean plant begins to form a fruit.
The major use of the velvet bean is manure for small farms. It is resistant to many pests and diseases, including ones that normally attack legumes. In several African and Asian countries, the velvet bean is used as a minor food, as it is a rich source of protein. It can be made into a garnish, condiment, or picked when immature to use as a vegetable. The overall nutritional value of the velvet bean is comparable to that of more commonly eaten legumes, such as soybeans, cowpeas, and groundnuts.
Mucuna pruriens are also used as animal feed in some countries. The plant, however, can be toxic to humans and other nonruminant mammals if eaten uncooked. The cooking process rids the plant of chemicals such as levodopa, which makes it otherwise unsuitable for consumption in large quantities.
The bean has been used as treatment for Parkinson's Disease, though, as of 2010, no data supports its ability to work or the long-term tolerability. The bean contains levodopa and can been used to increase dopamine production in order to treat varying disorders, including depression and sexual dysfunction. Side effects are many and include hair loss, extreme emotional states, and hallucinations. As the bean also contains serotonin and nicotine, it could possibly be a mind altering substance.