The term adaptogen was invented in the former USSR. An adaptogen increases body resistance to physically, chemically or biologically noxious factors, thereby having a normalizing effect on body functions and inflicting no harm. Most of the research took place in the USSR and in Scandinavian countries and was not published in English. In the last decades, some research has been performed in Western Europe and in the USA and was also published in English. From the research it is possible to learn about the efficacy of the adaptogen use as a single dose and on long term use and the differences between the various adaptogens. In this article there is a review of the studies and explanations of the adaptogenic activity. Adaptogenic effects on different functions in humans and animals are mentioned