Black Bean

The toxic compound phytohaemagglutinin, a lectin, is present in many common bean varieties. Phytohaemagglutinin can be deactivated by boiling beans for ten minutes; the ten minutes at boiling point (100 °C (212 °F)) are sufficient to degrade the toxin, but not to cook the beans. The primary symptoms of phytohaemagglutinin poisoning are nausea, vomiting, and diarrhea. Onset is from one to three hours after consumption of improperly prepared beans, and symptoms typically resolve within a few hours.