Oxidative stress, a it’s causes and effects on human organism, is a subject of interest of many scientific studies during the last decades. Today, it is clearly confirmed, that oxidative stress arises as a result of overproduction of free radicals while breaking the balance of antioxidant mechanisms in the body. On the basis of scientific studies it has been prooved that oxidative stress contributes to a number of very serious diseases. Currently the oxidative stress is often associated with the creation of cardiovascular diseases and cancer. Besided weight of genetic factors, which play an essential role in the etiology of these diseases, these diseases can be effectively prevented mainly by healthy lifestyle and healthy eating. It is well known that fruits and vegetables contain a balanced ratio of healthy substances and they are also the most important source of antioxidants in the human diet. Among the most important substances with antioxidant activity, present in fruits and vegetables, carotenoids, tocopherols and flavonoids should be mentioned. Most studies that examined the antioxidant activity of these compounds in the context of developing the disease or their further progress, confirmed a positive relationship. Many of these effects are studied on model animals and the results thus obtained are still reviewed, disseminated and applied in clinical and interventional studies.