Phytohemagglutinin is a toxic agent found in many beans, but in highest concentration in red kidney beans.

Health considerations

Consumption of phytohemagglutinin, through as few as 4 or 5 insufficiently cooked kidney beans, can cause nausea, vomiting, diarrhea, and severe abdominal pain. Symptoms usually dissipate on their own after three to four hours.

Keep in mind

Phytohemagglutinin is a glycoprotein, lectin, which requires a sufficiently high temperature to be inactivated. Slow cookers, and simmering at low temperatures, can increase the potency of the toxin. Soaking for a minimum of five hours and boiling for a minimum of ten minutes, with some agencies recommending thirty.

May be found in

Raw or insufficiently cooked: red kidney beans, white kidney beans, broad beans

U.S. Food and Drug Administration

Alternative Spellings and Names

Kidney bean lectin

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