White Spot Syndrome Virus (WSSV) is an extremely virulent, contagious, causative agent of the White spot syndrome of shrimp and causes high mortality and affects most of the commercially important cultured marine crustacean species globally. Oral administration of ethanolic extract and purified compound from the leaves of Pongamia pinnata, an indigenious Indian "medicinal plant" "has increased the survival of WSSV infected Penaeus monodon". Pelletized feed impregnated with ethanolic extract of the leaves of P. pinnata was fed to shrimp prior and after WSSV infection at 200 and 300 microg/g of body weight of shrimp/day. The survival rate for the WSSV-infected shrimp that were fed with 200 and 300 microg extract/g were 40% and 80%, respectively. The active WSSV antiviral compound 1 that was isolated from the leaves of P. pinnata was identified as bis(2-methylheptyl)phthalate. Thus, the present work revealed that oral administration of the crude and purified compound from the leaves of P. pinnata effectively inhibited WSSV pathogenesis and reduced the mortality of infected shrimp.