Lima Beans Contain Cyanide (But They're Still Safe to Eat!)

Yes, you read that right: those unassuming lima beans sitting in your pantry contain a compound that produces cyanide—the same poison used in spy movies. But before you toss out every can of succotash, there's some important context you need to know.

Lima beans contain linamarin, a cyanogenic glycoside. On its own, linamarin is completely harmless. The trouble starts when you bite into a raw lima bean. Chewing disrupts the bean's cells, triggering an enzyme that breaks linamarin apart into its component molecules—including hydrogen cyanide. That bitter, acrid taste some people associate with lima beans? That's actually your body's warning system detecting trace amounts of this compound.

Wild vs. Domesticated: A Dramatic Difference

Not all lima beans are created equal. Wild lima beans—the kind you might find growing in Costa Rica, Mexico, or Nigeria—can pack a serious punch, containing between 3,000 and 4,000 mg of cyanide per kilogram. That's enough to cause genuine poisoning if eaten raw in significant quantities.

Commercially grown lima beans in the United States, however, are a different story. The USDA requires that commercial varieties contain less than 200 mg of cyanide per kilogram, and most actually clock in between 100-170 mg/kg. Plant breeders have spent decades selecting for lima beans with lower linamarin levels, making modern varieties far safer than their wild ancestors.

Your Kitchen's Secret Weapon: Heat

Here's the good news: cooking lima beans doesn't just make them taste better—it neutralizes the cyanide threat almost entirely. The enzyme responsible for converting linamarin into cyanide is destroyed by heat. Boiling lima beans for just 10 minutes renders them safe to eat, while a thorough 30-minute boil in plenty of water removes about 80% of the original cyanide.

This is why you'll never hear about lima bean poisoning at restaurants or from canned varieties. The canning process involves high-temperature cooking that eliminates any risk. Even dried lima beans become perfectly safe once you've given them a proper boil.

Why Don't We All Drop Dead?

Even if you did consume a small amount of cyanide from undercooked lima beans, your body has defenses. Humans can metabolize small quantities of cyanide, especially when we're getting adequate protein in our diets. The sulfur-containing amino acids in protein help your body break down and eliminate cyanide before it can cause harm.

In fact, lima beans aren't the only common food with cyanogenic compounds. Cassava, almonds, apple seeds, and cherry pits all contain similar substances. The difference is dose and preparation—and as long as you're cooking your lima beans properly, the dose is negligible.

The bottom line? Lima beans do contain cyanide precursors, making this fact technically true. But thanks to agricultural breeding, food regulations, and the simple act of cooking, they're one of the safest foods in your kitchen. Just skip the raw lima bean salad, and you'll be fine.