Boerhaavia diffusa,a commonly known as punarnava in Sanskrit, is a herbaceous plant of the family Nyctaginaceae. The whole plant of its specific parts (leaves, stem, and roots) are know to have medicinal properties and have a long history of use by indigenous and tribal people in India. The medicinal value of this plant in the treatment of a large number of nhuman ailments is mentioned in Ayurveda, Charaka Samhita, and Sushrita Samhita. It has many ethnobotanical uses (the leaves are used as vegetable; the root juice is used to cure asthma, urinary disorders, leukorrhea, rheumatism, and encephalitis), and is medicinally used in the traditional, Ayurvedic system. Besides, the B. diffusa plant is reported to posses many pharmacological, clinical and antimicrobial properties. Recently, the authaors observed potent antiviral efficacy of this plant against phytopathogenic viruses. The antiviral agent isolated from this plant was found to be a glycoprotein with a molecular weight of 16-20kda. Administered by foliar spraying in the field, this antiviral agent natural infection by plant viruses.