Display omitted •Synthesized Ag and ZnO Nanoparticles via leaf extract of henna plant.•Acute oral toxicity and histopathology studies were done.•Showed non toxicity on tested mice for the period of 14days.•Histopathlogical changes have been studied. The Ag and ZnO nanoparticles are synthesized by a green method using Lawsonia inermis plant extract. The phytochemical constituent (2-hydroxy-1, 4-napthoquionone) found in the leaf extract of Lawsonia inermis plays an important role in the reduction and formation of Ag and ZnO nanoparticles. The biosynthesis of Ag and ZnO NPs was observed by the color change from colorless to dark brown and light brown. The FE SEM, TEM DLS analysis confirmed the average particle size of Ag and ZnO NPs as 100nm, 20nm, 28.5nm and 100nm, 20nm, 38.4nm respectively. Crystalline nature and presence of Ag and ZnO NPs were confirmed by XRD. The FT-IR spectra of the Ag and ZnO authorized the presence of phyto constituents as capping agent. From results of acute oral toxicity studies, it was found that Ag and ZnO NPs at 2000mg/kgb.w have shown no mortality during the treatment period. The present study revealed the safer use of eco-friendly green synthesized Ag and ZnO NPs in the field of nano-biomedicine.