This book contains the phytochemical screening and in vitro antioxidant activity of aqueous and hydroalcoholic extract of medicinal plant Bacopa monnieri. Bacopa monnieri which is generally known as Brahmi is used widely as a nervine tonic.It has wide medicinal applications. We tested the antioxidant activity of it using some standard in vitro assays such as Hydrogen peroxide assay , Ferric reducing power, Nitric oxide reducing assay , Superoxide reducing assay etc. From the test we concluded that the plant has the potential to reduce the free radicals or reactive oxygen species thereby can be used as an potent antioxidant apart from nervine tonic.