INTRODUCTION
In terms of prevention and treatment of diseases, medicinal plans are of particular importance in medicine.[1] Given the importance of these plants in medicine, extensive researches have been performed in recent years to extract and characterize active products of herbal medicine.[2] Proven beneficial effects of these plants, cheap and low expense, and compatibility with the environment are the most important reasons of using medicinal plants.[3,4] The results of studies have shown that some active ingredients of medicinal plants are useful for pain relief.[5] Findings have also shown that some medicinal herbs have antioxidant and anti-inflammatory effects in vitro.[6,7] In addition, some medicinal plants are widely used for different therapeutic purposes including treatment of gastrointestinal tract and digestive diseases caused by microbial contamination.[8] In this regard, various indigenous medicinal plants such as Cassia siamea, Flueggea virosa, Terminalia bellirica, and Terminalia chebula are used in different communities for the treatment of certain diseases such as malaria and gastrointestinal disease or as remedy in infants and children.[9] It is estimated that close to 80% of people in different communities use different types of traditional medicine for the treatment of various disease.[10] Nowadays, the use of natural remedies even in developed countries has become prevalent and these herbal products are routinely used in 18% of pediatrics institutions and 94% of other communities in Canada only for the treatment of various disease in children.[11] It is shown that near to 20,000 herbal products are currently available on the market overall the world, and the annual trade turnover of medicinal plants is approximately 4 billion dollars only in the United States.[12]
Besides their known beneficial properties, studies have shown that some medicinal plants such as Ephedra species, Aconitum species, Datura species, and Lobelia species in long-term use have strong toxic effect particularly in the children.[13,14,15] Toxicological studies of medicinal herbs on animal models have shown that some of these plants such as daouri and juniper tar that are typically used to treat chronic eczema and other skin diseases may have nephrotoxicity or hepatotoxicity, suggesting that the use of these plants particularly in children should be reevaluated.[16,17] Although it has been shown that natural or complementary and alternative medicines, particularly medicinal plants, have fewer side effects than chemical drugs, studies have shown that herbal medicines are not all safe for direct human use, especially in pediatric patients.[18,19] The importance of acute poisoning is greater in children and especially neonates since their digestive and immune systems are not completely evolved. On the other hand, children are not aware of the dangers associated with the ingestion of every material. Studies have shown that although the overall number of mortality due to toxic plants is low, yet they are considered as an important cause of morbidity and mortality.[20] On the other hand, since the toxicological information and antidote therapy of some medicinal herbs is not available, plant toxicity deserves greater attention.[21] Since there are great concerns about the toxicological impact of medicinal plants in human, particularly in sensitive age groups, in this study, we aimed to systematically review the literature wherein toxicological impact of medicinal plant had been investigated in children. In addition, we aimed to introduce the plants that have been reported as poisonous, at least in children, to warn the health professionals about the consequences of consciously or unconsciously use of herbal medicine.