[Human allergic hypersensitivity and chemical residues in food]

Chemical and immunological basis of hypersensitivity reactions to low molecular weight substances are recalled. Then the authors give examples of directly reactive chemicals as penicillins and some antineoplastic drugs. The possible role of reactive impurities as penicillins and aspirin is also reminded. It is emphazised that some substances induce allergic reactions through their metabolites: such reactions are mostly unforeseeable. The second part of the paper recalls the main clinical manifestations of these allergic hypersensitivity reactions to chemical residues in food. It is finally emphazised that the datas from animal experiments and epidemiological studies could allow a classification of chemical substances according to their potential risk. This would be of great importance to determine which substances may be authorized in food stuffs and/or to specify the maximum allowable concentrations.