Poly(vinyl alcohol) (PVA) capped stable silver nanoparticles (AgNP) have been synthesized sonochemically with the help of catalytic amount of a biomolecule (tyrosine). An attempt has been made to reduce the harmfull chemical additives (like sodium borohydride, hydrazine, dimethyl formamide, etc.) used in conventional methods. Tyrosine shows excellent reducing activity in presence of PVA stabilizer. Ultrasound increased the reaction rate and yield, and improved the quality of the AgNP in terms of regular size distribution. The synthetic route follows the principles of green chemistry. Bioactivity has been tested in the light of antifilarial efficacy through induction of apoptosis. The biocompatible polymer (PVA) capped AgNPs are suitable for the treatment of filarial nematode. (C) 2013 Elsevier B.V. All rights reserved.