The Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) have served as scientific advisory bodies to the Codex Alimentarius Commission, to member countries and other interested parties since the 1960s. Considerable changes have taken place in the procedures and complexity of assessments of chemicals in food since the preparation of the original guidance documents for the work of JECFA and JMPR (EHCs 70 and 104). In order to reflect significant advances in chemical analysis, toxicological assessment, and risk assessment procedures, this detailed monograph on the methods and principles for the risk assessment of chemicals in food was developed.