Though there are nutritional advantages to consuming vegetable fat that is rich in poly-unsaturated fatty acids (PUFA's), this can also entail health hazards that are linked to their potential oxidative deterioration. This oxidative deterioration can be the outcome of numerous and varying causes. This publication examines these causes as well as the different kinds of oxidation products in the light of what is known about their toxicity for humans. Though our knowledge in this field has increased, we are left with many partial data, or even a lack of data, especially as regards the ingestion of oxidised products via food. It is therefore almost impossible to carry out a thorough risk assessment on the basis of the data that are currently available. The nutritional recommendations hold that the proportion of oils that are rich in poly-unsaturated fatty acids of the omega-3 and omega-6 type should be increased compared to that of the remaining fatty products consumed. Yet in order to enable their implementation, greater attention should be paid to the manner in which the different products are made, stored and used. These recommendations are aimed not only at the industry, the public authorities and the hospitality business, but also at consumers. Priorities were set on the basis of current knowledge about potential hazards. The main hazard is posed by 4-hydroxy-2-nonenal (4-HNE), its potential presence in food intended for babies and young children, as well as its effects on health. ; BE; fr; info.hgr-css@health.belgium.be