One of the foods with the highest amounts of lectin are red kidney beans and as few as 5 under-cooked red kidney beans can cause severe symptoms of bloody vomiting and food poisoning.
Cooking at high heat deactivates lectin and makes the beans safe to eat. And while many of the other beans such as white kidney beans and Greek butter beans contain lower amounts of lectin, caution is advised with any type of beans.
Beans, peas and related products should always be soaked in water for at least 12 hours before cooking, with the water being changed frequently. Adding baking soda to the soaking liquid will help in neutralizing the otherwise toxic lectins.
Lectins are also found wheat, seeds, beans, soy, legumes and a variety of night shade products such as eggplant, potatoes, tomatoes and peppers.