Medicinal and aromatic plants constitute an important part of natural environment and agro-ecosystems, and contain an enormous type of chemical compounds known as secondary metabolites including alkaloids, glycosides, essential oils and other miscellaneous active substances. Most of the pharmaceuticals properties of plants have been attributed to these compounds. In recent years there has been a growing interest to the use of bioactive compounds from natural sources. In the report commissioned by the World Health Organization (WHO), it is pointed out that 80 percent of the population of developing countries relies on traditional plant based medicines for their primary health requirements. However, these metabolites help plants respond to environmental and or any external stimuli in a rapid, reversible and ecologically meaningful manner and therefore, play critical role in existence of plants in any environment. In the other hand, the environmental factors play a crucial role in regulating the metabolic yield of these biologically active molecules, and dynamic response of these metabolites is one of the factors explaining plant’s adaptation strategy. Therefore, growth, development and maintenance of medicinal and aromatic plants as well as their metabolites content are influenced by a wide range of unexpected environmental biotic and abiotic factors such as high and low temperature, climate change, global warming, UV-irradiation, high light and shade, ozone, carbon dioxide, drought, salinity, nutrient deficiency, agrochemicals, waste, heavy metals, nanomaterials, weed, pest and pathogen infection. Changes can occur in the course of the plant cycle and even during one single day. Therefore, medicinal plants face many environmental challenges affecting both human health and wild and field ecosystems. Understanding medicinal plants response to environmental perturbations and climate change could open new frontiers in plant production and in agriculture where successive
