* * can't * *, cold hanging beans won't cause poisoning. Hanging beans are cowpeas and can be eaten raw. Eating only raw or undercooked green beans, also called kidney beans, is easy to cause poisoning. This is because raw beans contain two kinds of bean substances harmful to human body: hemolysin and toxic protein. When people eat raw beans, these two toxins have a strong stimulating effect on the gastrointestinal tract, ranging from abdominal discomfort to vomiting and diarrhea.