This might be shocking to you, but certain types of beans can be quite poisonous. Did you know that red beans were legally prohibited from being imported into South Africa because of “their potential toxicity to humans”? The main cause is a toxin called ‘phytohaemagglutinin’ or kidney bean lectin. This is a sugar based protein (glycoprotein) which is found in many types of beans such as cannellini beans. However, red kidney beans contain the highest concentrations of this toxin. It only takes a few beans to cause nausea, vomiting, diarrhea, abdominal pains.