Herbal drugs are essential components of traditional medicine in several countries viz. India and China, where ancient civilization was flourished heritage. India has a well-established system of medicine known as Ayurveda. Ayurveda utilizes plants, animal and minerals for the welfare of human beings. Ayurvedic approach is mostly focused on longevity to keep person healthy rather than cure. Therefore large number of ayurvedic formulation s are based on plants. Now-a-days plants are being explored for number of purposed i.e. energy to medicine. Despite their popularity, there is paucity on the information their availability in the plants, variation within plants, assay procedures and rapid screening techniques. In this book we have tried to deal these issues. 101 indigenous medicinal plants were selected to study their efficient role as antioxidant. The DPPH assay was applied for evaluation. Two mathematical models. Viz. Non-linear regression (3rd degree polynomial) and Sigmoidal dose-response (variable slope) fit, to compute the result. The variation due to selection of model was discussed. FTIR and HPLC fingerprinting of selected plants was also presented.