Neurolathyrism is a spastic paraparesis that can be caused by excessive consumption of the drought-resistant grass pea (Lathyrus sativus). Devastating neurolathyrism epidemics have occurred during major famine crises in various parts of the world. We investigated in a case-control study the effects of food aid on risk of paralysis. Risk increased with consumption of boiled grass pea (adjusted odds ratio 2.78, 95% CI 1.09-7.13 with cereals; 5.22, 2.01-13.55 without cereal) and raw unripe green grass pea (1.96, 1.16-3.31; p=0.011), but not with the fermented pancake, unleavened bread, and gravy preparations. In a correlational study there was an inverse relation between the number of new cases and the amount of food-aid cereals distributed per person. During famine, cereals and nutritional information should reach people before they have grass pea as the only food.