Medicinal herbs as potential source of therapeutics aids has attained a significant role in Health system all over the world for both humans and animals not only in the diseased condition but also as potential material for maintaining proper health. A major factor impeding the development of the medicinal plant based industries in developing countries has been the lack of information on the social and economic benefits that could be derived from the industrial utilization of medicinal plants. Except for the use of these plants for local health care needs, not much information has been available on their market potential and trading possibilities. The present review mainly focuses on some medicinal plants with their biological sources, chemical constituents, usual doses and adverse effects. Traditional medicines are generally considered safe due to long history of being in practice especially under the specified conditions for use reported in ancient literature. However, adverse effects in some individuals due long-term use of certain herbal drugs have been reported recently. The adverse effects range from liver failure (comfrey root) to abnormal heart rhythms (ephedra) to death (pnnyroyal). World Health Organization advocates use of herbs that have along history of use only if no adverse events have been reported. In case of herbals where some adverse effects are reported, toxicity data in its dosage form is required using all toxicity bench –marks for conventional pharmaceuticals. Isolated active principles from herbals are to be treated like modern drug and subjected to rigorous testing as required by the regulatory authority of thecountry. Another concern related to safety of herbals is presence of contaminants such as heavy metals, persistent pesticides and afltoxins.
