Toxins in Beans

Green beans, red kidney beans, and white kidney beans - contain naturally a toxin known as phytohaemagglutinin. Food poisoning caused by this toxin in raw and inadequately-cooked beans has a short onset time (1-3 hours) with symptoms of nausea, vomiting and diarrhoea. However, this toxic substance can be destroyed by soaking and then cooking thoroughly at boiling temperature. Tinned beans which have been subjected to thorough heat-treatment are safe to eat without further cooking.