Chronic poisoning by hydrogen cyanide in cassava and its prevention in Africa and Latin America

Food Nutr Bull. 2002 Dec;23(4):407-12. doi: 10.1177/156482650202300416.


Africa produces more than 30 million tons of cassava on about 5 million hectares (6 tons per hectare). Approximately 80% of the root production and 70% of the harvested area are from Western Africa. Recent reports suggest that the ingestion of poorly processed cassava roots is associated with the incidence of an ataxic neuropathy (konzo) in African countries. When cassava-based diets are not supplemented with good sources of protein and iodine, goiter and rickets are also prevalent. In certain countries of Africa where the rate of ataxic neuropathy is high, the incidence of thyroid disorders is also high. Persons consuming poorly processed cassava in large quantities are susceptible to neuropathologies caused by cyanide. Cyanide detoxification in the body is impaired by protein deficiency. When properly processed, the root of cassava is safe and cheap as a major dietary energy source for humans and domestic animals; however, a cassava-based diet will lack sufficient protein and will be particularly deficient for the growth and development of children unless it is supplemented by protein from animal, including fish, or legume sources. Cassava leaves, if they are appropriately cooked, can be a useful source of some nutrients.

Publication types

  • Review

MeSH terms

  • Acute Disease
  • Africa
  • Animal Feed
  • Chronic Disease
  • Consumer Product Safety
  • Cooking / methods*
  • Humans
  • Hydrogen Cyanide / poisoning*
  • Latin America
  • Manihot / chemistry*
  • Manihot / poisoning
  • Motor Neuron Disease / epidemiology
  • Motor Neuron Disease / etiology
  • Nutritive Value
  • Plant Poisoning / complications
  • Plant Poisoning / etiology*


  • Hydrogen Cyanide