Pesticides having a rapid and positive influence on the quantity of produced food, at the same time are involved in several side effects, often creating some hazard to human health and well-being. The authors show these facts in view of the possible entrance of these substances into the food chain, and present several actions or measures undertaken by various organizations, especially UN Agencies. The main emphasis is laid down on pesticides residues which remain in consumed food, based on the experience gained in different countries including Poland. From the toxicological or health point of view, it is important to know whether these substances interact with other nutrients entering plant or animal tissues or whether they remain on the surface, being easily removed before human consumption. Some effects of processing on decreasing the content of these residues in foodstuffs are also briefly outlined. Another aspect connected with the application of pesticides is their influence (mainly negative) on the nutritive value of harvested plants. In conclusion, the authors call for more attention and a complex approach in using pesticides for plant and animal protection as well as basic and applied nutrition, or health-oriented research along with training activity within national or rather international (e.g. UN Agency) programmes. They should be aimed at the optimal application of pesticides on modern agricultural practices with the main emphasis on their nutritional implication.