Poisonous plants are one of the most important causes of poisonings in human. Although most of plant-induced poisonings are mild in terms of severity but they may be life-threatening. Regarding compositions of toxic plants, most of them can induce toxicity on many biological systems including central nervous system, cardiovascular, hematopoietic sytem and etc. In this brief review, we tried to summarize demonstrations of toxicity and adverse effects of poisonous plants and their active substances on biological systems, and thir clinical management.