A healthy diet can reduce the risk of non-communicable diseases, including cardiovascular disease and some types of cancer. In general, a diet rich in fruits, vegetables, whole grain cereals, legumes, and nuts, in which products of animal origin are limited, according to the model of the Mediterranean diet, can help prevent the onset of chronic degenerative diseases, together with other lifestyles. This narrative review presents the most representative classes of bioactive phytochemicals and the main Mediterranean foods in which they are present, providing evidence in humans of their health-promoting effects. Keywords: functional foods, nutraceuticals, plant foods, Mediterranean diet, nutritional therapy, non-communicable diseases, disease prevention