India being a rich and varied flora of medicinal plants since the Vedic period. The present study deals with the scientific validation of medicinal plants - Andrographis paniculata Nees. (Kalmegh or green chiretta ) with special reference to its pharmacognostical investigations. Kalmegh or green chiretta and is known to have medicinal properties, also even used as home remedies in the rural and the remotest parts of the India. The Andrographis paniculata used as anti-diabetes, antioxidant, anti-inflammatory, antidiarrhoeal, antiviral, antimalarial, hepatoprotective, anticancer, anti-human immunodeficiency virus (HIV), immune stimulatory and antisnakebite activity.