Chronic diseases have become the largest contributor to worldwide morbidity and mortality. Healthy diet represents an effective primary intervention measure in combating the onset of chronic diseases, and epidemiological studies had documented that Mediterranean foods are associated with low incidence of chronic diseases. Mediterranean diet is a combination of vegetables, fruits, moderate amounts of fish, white meat and some dairy produce. One key aspect of the Mediterranean diet is the inclusion of olive oil, nuts and fish. This chapter aims to clarify the positive effects of Mediterranean foods, mainly olive oil, polyphenols, nuts and fish in relation to human health and therapeutic properties.