Plant-based diet is an old-new trend in nutrition. In this review based on a historical context, we wish to introduce this popular nutritional trend. Our aim is to present plant-based diet as a primary measure for prevention. We intend to critically analyse some past stereotypes related to plant-based diet - whose main components include fruits, vegetables, whole grains, legumes, nuts and seeds - according to the literature (e.g. protein, vitamin B12, folic acid, and iron intake) by doing so we wish to create an adequate conceptual basis for its interpretation. We discuss positive physiological effects of plant-based diet and its possible role in diseases risk reduction. Cardiovascular and metabolic diseases developing due to obesity could be prevented by a properly compiled plant-based diet. For patients with cancer minimizing the intake of foods of animal origin - as opposed to plant-based ones - has proved to have positive effects. Our review suggests this diet can be used in a number of diseases and it also provides long-term sustainable solutions for the health care challenges of the newest era. Orv. Hetil., 2016, 157(47), 1859-1865.