Red Kidney bean poisoning is esp. common in UK where kidney beans are more commonly used. Caused by the toxin phytohaemagglutnin which may be found in all beans but is much more common in the red kidney bean. Boiling in fresh water for 10 minutes after soaking for 5 hours-overnight eliminates most of it and one should have no symptoms. Slow cooking, or crockpot cooking at 80 C actually strengthens the toxicity of the poison.
Canned beans have been processed at high temperature, so no danger.

Symptoms are stomach pain, nausea and vomiting, and diarrhea. Generally, the symptoms last only a few hours; the condition is not dangerous.
http://www.foodreference.com/html/artredkidneybeanpoisoning.html