Calabar Bean

Physostigma venenosum, the Calabar bean or ordeal bean, is a leguminous plant in the family Fabaceae, endemic to tropical Africa. It is a large climbing perennial that reaches about 15 metres, and its seed is poisonous to humans. The seed contains physostigmine and other indole alkaloids. The people of Old Calabar in present-day Nigeria used the beans, which they called E-ser-e, as an ordeal poison: they gave them to persons accused of witchcraft or other crimes, and a person who ate the beans and did not die was considered innocent, because the bean was believed to affect only the guilty. A form of duelling with the seeds was also practised, in which two opponents divided a bean between them. The article reports that in 1864 at least forty-six children in Liverpool were admitted to hospital with severe vomiting and abdominal pain after eating beans from sacks of rubbish dumped on waste ground. Atropine is named as the main antidote.