Biocontrol of pathogens is an important and useful way for avoiding the side effects caused by synthetic antibiotics and chemicals and
controlling the emergence of antibiotic resistant pathogens. Hence the present study was focused to control the five harmful human
pathogens Shigella boydii, Staphylococcus aureus, Klebsiella vulgaris, Shigella dysentriae Salmonella typhi in bio control methods
using five common medicinal plants Cassia auriculata, Cassia alata, Cassia occidentalis, Cassia roxburghii and Caesalpinia
pulcherrima by screening their antibacterial activity, synthesizing the silver nano particles and its antimicrobial activity. The synthesis
of plant based silver nano particles were confirmed by the colour change from pale green and dark orange. Among the five plants C.
auriculata extract nanoparticles showed maximum inhibitory effect compared with other four plants based nano particles. The
antibacterial activity exhibited by the silver nano particles of all the selected medicinal plants was very high compared to the inhibition
of positive control ciprofloxacin. In plant silver nano particles all the inhibition zones were observed in between 14 mm – 22 mm.