The histopathology of three fungicides on gall-bladder structure in frog Pelophylax ridibundus were investigating by light microscopy. The frogs were experimentally exposed to sub-lethal concentration of the fungicides. The toxic substances were administered by intraperitoneal shots, one shot every two days, in a scheme of 3 weeks. Tissues samples were fixed in 8% neutral formalin and processed using histological method. The epithelial metaplasia was observed as response to the harmful action of the toxic and the presence of leukocyte infiltrations.