Konzo is characterized by the abrupt onset of isolated and symmetric spastic paraparesis of the lower extremities which is permanent but nonprogressive. Epidemic outbreaks in subtropical and tropical regions are associated with drought-provoked agricultural and social crises rendering populations dependent on a diet of insufficiently processed bitter cassava. The shortcuts in processing allow large amounts of cyanogens to remain in the cassava consumed and hence there is a high dietary cyanide exposure. Mainly children and ill people, often malnourished (and with kwashiorkor), are not able to detoxify the cyanide sufficiently, consequently developing symptoms of upper motoneuron damage. Konzo generally seems not to be caused by ignorance concerning the correct processing of cassava, but predominantly directly and indirectly by poverty.