This book consists of detailed pharmacognostic, phytochemical and pharmacological study of Ruellia tuberosa. Ruellia tuberosa is an herb, 30-45 cm height, erect, sub-erect or diffuse perennial stem with purple or deep blue colored flower. Fruit bluish, purple or deep blue, the ripe seed capsules of Ruellia tuberosa, when come in contact with water, it breaks open with force and an audible sound is reported and dispersing seeds away from the plant. This explosive behavior gave the plant local name in English "Cracker plant". HPTLC fingerprinting of various extracts of roots, leaf and stem of R. tuberosa have been also included. Marker compound is identified, also isolated and quantified in root extracs. Antioxidant and anti-diabetic activity were also carried out as per reported method.