Calabar Bean

Scientific Name(S): Physostigma venenosum. Family: Leguminosae (Fabaceae).

Common Name(S): Calabar bean, physostigma, ordeal bean, chop nut, esere nut, faba calabarica.

Botany: The calabar bean is the dried ripe seed of the P. venenosum, a perennial woody climbing plant found on the banks of streams in West Africa. Vines of the plant extend more than 50 feet in the air, climbing high among
the trees. The plant bears showy purple flowers and seed pods that grow to about 6 inches in length. Each pod contains from 2 to 3 seeds. The dark brown seeds are about 1 inch wide and thick and have an extremely hard shell.

History: This plant is native to an area of Africa around Nigeria once known as Calabar. The plant is widely known in Africa because the seeds had been used as an .ordeal poison" to determine if a person was a witch or possessed by evil spirits. When used for this purpose, me victim was made to ingest several beans; if the person regurgitated the beans and survived the "ordeal," his innocence was proclaimed. Western settlers who were captured by native tribes and who underwent the "ordeal" soon learned not to chew the bean, but to swallow the kidney-shaped bean intact, thereby not permitting the release of the toxic constituents. The plant has been long recognized as a commercial source of the alkaloid physostigmine, first isolated in 1864.

Uses of Calabar Bean

Originally consumed in African ritual ordeals which killed many subjects, the bean produces alkaloids clinically used to contract the pupil, manage ocular pressure in glaucoma, reverse toxicity of certain other drugs, and treat myasthenia gravis.

Side Effects of Calabar Bean

Toxic principle affects heart and induces respiratory paralysis.

Calabar Bean Safety & Interaction Information
Calabar Bean is a poison and can be fatal. If poisoning should occur, the stomach should be evacuated and antropine injected until the pulse quickens.

Summary: The use of the calabar bean as an "ordeal bean" has long been outlawed in Africa, although its use persists in tribal ritual. The bean is the source of physostigmine, a medically valuable drug that prolongs the activity of the neural transmitter acetylcholine. Physostigmine is highly toxic.