Cassava is eaten by nearly 500 million people worldwide and is a critical staple crop across Africa, South America and Asia. Yet the World Health Organization reports that over 200 people die every year from consuming it — earning it the label of the "world’s deadliest food." The danger lies not in the plant itself, but in how it is prepared.
In brief
- —Over 200 deaths per year linked to cassava, per the WHO
- —Cyanide released when cassava is improperly processed
- —Soaking for 24 hours is key to making it safe
A staple crop for 500 million people — and a source of cyanide
Cassava is one of the most widely consumed foods on the planet. Originating in South America, it is grown by the hundreds of millions of tons each year and serves as a primary food source for populations across sub-Saharan Africa, Latin America and parts of Asia.
Despite its central role in global food security, the plant carries a serious chemical risk. Its stems, peel and leaves contain cyanogenic glucosides — compounds that act as a natural defense against animals and insects. When these glucosides are not neutralized through proper processing, cassava can release hydrogen cyanide, a substance that is potentially fatal.
Why cassava remains essential despite the risk
Cassava is drought-resistant, grows in poor soils and produces high caloric yields — qualities that make it indispensable in food-insecure regions. It is one of the few crops that can sustain populations through difficult growing conditions, which is why hundreds of millions of people depend on it even where safer alternatives are scarce.
More than 200 deaths a year, and a disease that causes irreversible paralysis
The World Health Organization reports that around 200 people die annually from eating improperly prepared cassava. The WHO states: "Cassava tubers contain varying amounts of cyanogenic glucosides that serve as a defense against animals and insects. When these glucosides are not processed correctly, cassava can release cyanide, leading to high dietary cyanide exposure."
This toxic exposure is especially prevalent during periods of famine and armed conflict, when food choices are severely limited and preparation time or resources may be lacking.
Chronic cyanide poisoning from cassava is directly linked to a condition called konzo — a debilitating and irreversible disease characterized by sudden paralysis of the legs. Konzo is most commonly found in regions of extreme poverty and can strike sporadically or in epidemics. The risk is compounded when bitter cassava is consumed alongside a low-protein diet, which reduces the body’s ability to detoxify cyanide.
Venezuela: a documented case of dangerous consumption during food scarcity
The risks of improperly prepared cassava are not theoretical. In Venezuela, people were reported to be consuming cassava in its hazardous form as a survival strategy during periods of acute food scarcity, relying on salty foods alongside it, according to reporting by El País.
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