ABSTRACT
Sesquiterpene lactones belong to the large group of plant terpenoids. In nature, sesquiterpene lactones play an important role in plant defense, as antibacterials, antivirals, antifungals, insecticides and by reducing the herbivores' appetites for such plants. They also have some allelopathic potential. In recent years there is an increasing interest in sesquiterpene lactones, mostly because of their cytotoxic and anticancer activity. This paper will summarize current knowledge about sesquiterpene lactones in plants.