IntroductionPoisoning is one of the most important health issues in the world. There is no exact statistic regarding the epidemiology of poisoning in Iran. The aim of this systematic review was to study the epidemiology of poisoning of adults in Iran.MethodsAll the published papers regarding the epidemiology and patterns of adult poisonings in different parts of Iran were reviewed in bibliographical databases, including SID, Iran Medex, Medlib, Magiran and Embase, Scopus, PubMed, and Google Scholar, without time limitation up to March 21, 2016. We searched for the terms poisoning, Iran, and epidemiology. After the final analysis, 38 articles that fulfilled all the required conditions were selected.ResultIn this article, we show that in most Iranian cities, except Ahvaz, pharmaceutical drugs, especially psychiatric pharmaceutical drugs, are the most common cause of poisoning in adults. In the Southwest region of Iran, poisoning due to envenomation is a very common. Although pesticide and opioid poisonings are less common, they are an important cause of death due to poisoning in Iran.ConclusionPharmaceutical drugs are the most common cause of poisoning in most Iranian cities and it is recommended not to store pharmaceutical drugs at home and to set special rules regarding proper description of pharmaceutical drugs. More public health instruction is essential in the Southwest cities of Iran in order to reduce animal poisonings.