Silver nanoprticles (SNPs) are invested in medical, industrial and environmental applications. Little if any, is known about the morphometric alterations induced by the toxicity of SNPs. The aim of the present work is to find out the effect of variable size of SNPs on different morphometric parameters. Adult healthy male mice (BAL/C) were subjected to (10 nm, 20 nm, 40 nm 60 nm and 100 nm) SNPs for 35 days. Silver NPs caused non-significant decline on the average weight, significant decline in food consumption, increase in water intake, unilateral blindness, tanning fur color and cholestasis together with a decrease in the relative ratio of the liver, kidney and spleen weight to body weight. Mice subjected to 10 nm and 20 nm were more affected than mice receiving larger nanoparticles. These findings may indicate that SNPs could induce morphometric alterations that are size related wheresmaller SNPs have more impact than the larger ones.

KEY WORDS: Silver nanoparticles; Morphology; Toxicology; Liver; Kidney; Spleen.