The article discusses a currently significant issue of administrative law regulations concerning foodstuffs and food additives. They both function in the law as dietary supplements. Distinguishing between dietary supplements and medicinal products is crucial, as it entails different law regulations, different registration procedures, and it allows to determine competent public administration authorities. If a product is considered a dietary supplement, it is then dealt with in terms of the Act on food and nutrition safety. As far as advertising of dietary supplements is concerned, it is not allowed to mislead consumers.