Résumé : During the school year 1999-2000, three nurses visited a number of Belgian schools to procure free information about female hygiene to girls 12 to 15 old. Using self-administered questionnaires, a sample of 5000 young male and female adolescents were at the same time interviewed about their food practices, way of life, living situation and the image they had of themselves. One out of four male teenagers in Wallonia and almost one out of five teenagers in Flanders declared to take one, or less than one portion of fruit and/or vegetables a day. In female teenagers, these figures amounted to 19,5% in Wallonia and 16,0% in Flanders. One out of ten male adolescents ate enough fruit and vegetable each day, 10.0% in Flanders and 13.2% in Wallonia. In female teenagers, these amounted to 15,0% in Flanders and to 14.6% for Wallonia. Our study noted a decline from 15.7% to 12.2% for the highest intake of fruits and vegetables by female adolescents between 14 and 15 years old. Once 15 years old, almost one adolescent out of three (28.4% in males and 28.9% in females) declared to take one or less than one portion of fruits and/or vegetables a day. No aliments except fruit and vegetables have ever proved to exert a more beneficial effect on health as regards a reduction of morbidity and mortality. These facts are established since more than 20 years, but are still largely overlooked by the lay public. Most Belgian citizens believe that many food products are unhealthy because of their contamination with dioxins, addition of antibiotics and hormones, and presence of pesticides. However, intake of unsaturated fatty acids, fruits and vegetables exercise a much greater influence on mortality and morbidity.