This book provides an evaluation of measures to reduce exposure to highly toxic and carcinogenic contaminants in staple diets in Africa as well as parts of Asia and Latin America. Many of the poorest people in these regions are exposed to the pervasive natural toxins, aflatoxins and fumonisins, on a daily basis by eating their staple diet of groundnuts, maize, and other cereals. Exposure to mycotoxins at these high levels substantially increases mortality and morbidity. Aflatoxins are a cause of human liver cancer, and fatalities from acute aflatoxin poisoning outbreaks occur in Africa and Asia. The International Agency for Research on Cancer convened a Working Group of world-leading experts to review the health effects of aflatoxins and fumonisins and to evaluate intervention measures. The panel concluded that these mycotoxins not only are a cause of acute poisoning and cancer but also are a likely contributor to the high levels of stunting in children in affected populations. The Working Group also identified effective measures to reduce exposure in developing countries. The panel evaluated 15 interventions, considering the strength of the evidence as well as its completeness and its transferability at an individual, community, or national level. Four of the interventions were judged to be ready for implementation: improvement of dietary diversity; crop sorting; post-harvest measures, including improved storage; and, in Latin America for maize, optimized nixtamalization. These recommendations would be relevant for investment of public, nongovernmental organization, and private funds at the scale of the subsistence farmer, the smallholder, and through to a more advanced value chain.