Dietary supplement use is very popular among athletes, to enhance performance, speed recovery or ease pain. Many of these products contain numerous ingredients that are not prohibited substances in sport, such as amino acids, proteins, creatine and caffeine. However, unscrupulous manufacturers also use these nutritional supplements as cover-ups to sell prohibited substances, such as synthetic psychoactive drugs. These substances are commonly undeclared on the supplements label or identified with names of natural products, pretending to be harmless. The inclusion of novel psychoactive substances (NPS) in supplements is even more problematic because neither the parent compound nor the metabolites are detected in routine drug tests. This chapter describes the historic evolution of the use of dietary supplements containing psychoactive substances (PS) for sports doping and proposes means to curb their availability and consumption.