The “World’s Deadliest Food”: Why Millions Still Eat Cassava Despite the Risks

Cassava naturally contains substances known as cyanogenic glycosides. When the root is cut, crushed, chewed, or improperly processed, these compounds can break down and release cyanide, a highly toxic chemical. The amount varies depending on the variety of cassava and growing conditions. Some varieties, often called “bitter cassava,” contain significantly higher concentrations than “sweet cassava.”

For centuries, communities that rely on cassava have developed preparation techniques designed to reduce these toxins. Peeling, soaking, fermenting, drying, and thorough cooking can dramatically lower cyanide levels, making the root safe to eat. Problems arise when cassava is consumed raw, undercooked, or processed incorrectly.

Health experts have documented cases of poisoning linked to improperly prepared cassava. Symptoms can include headache, dizziness, nausea, vomiting, abdominal pain, and breathing difficulties. In severe cases, poisoning can be fatal. Long-term exposure to smaller amounts of cyanide from poorly processed cassava has also been linked to certain neurological disorders in regions where cassava is a dietary staple and food shortages limit proper preparation methods.