Athletes' nutrition, along with hard training, is one of the basic factors that affect the sports results. Athletes with ever more intense and stronger training have greater energy needs and less time for body regeneration, which is why they often consume various nutritional supplements in order to achieve the desired goal more easily and quickly. Since sports goals are set higher every day, athletes often consume various medications along with nutritional supplements because they think medications will improve their sports performance, without thinking of the consequences and side effects of consuming such products. The most common nutritional supplements that athletes use are vitamins, most of which vitamin B complexes, vitamin C, vitamin D and vitamin E, and calcium, magnesium and iron minerals; protein supplements, branched-chain amino acids (BCAAs) or branched chain amino acids; L - Carnitine and Creatine. When it comes to drugs, athletes usually come up with anabolic steroids, testosterone and growth hormone. In this thesis reserched the frequency of dietary supplements and medicines consumption on athletes. The research included 70 athletes and answeres which are the most commonly used supplements, their side effects, and the side effects of certain nutritional supplements and medications. Out of the 70 surveyed, 16 were female and 54 were male and 49 of them opted to use some dietary supplements and / or medicines. Thirty-two people noted the side effects, most of which were people with digestive problems, dermatological problems, hypertension, and heart failure disorders.