Be Careful With Red Kidney Beans in The Slow Cooker

Reader Contribution by Robin Mather
article image

When the weather is cold and raw, good cooks turn to their crockpots to provide the long-simmered dishes that winter appetites demand. We seem to hunger naturally for the flavors of chilis and soups, stews and pot roasts.

One favorite winter dish that requires a bit of caution, however, is the big bowl of crockpot beans. Red kidney beans — commonly added to chili — can be the source of Red Kidney Bean poisoning, caused by a toxin called Phytohaemagglutin, or kidney bean lectin.

Other beans also contain the toxin, but in varying amounts. Red kidney beans have 20,000 to 70,000 heagglutinating units (hau), while white beans contain about a third as much; broad beans like favas have as little as 5 percent of the amount in red kidney beans.

This toxin can make you feel pretty crummy. Raw or undercooked beans can cause nausea, vomiting, diarrhea and abdominal discomfort within 1 to 3 hours. Recovery usually is complete within 4 hours of the symptoms’ appearance, though some people have been hospitalized.

Fully cooked or canned beans are always safe to eat. But undercooking can actually raise lectin activity. That’s why it’s best to use canned or fully pre-cooked kidney beans in crock pot recipes that call for beans.

For more information, visit the Penn State Extension explanation at


Need Help? Call 1-800-234-3368