Metformin is an oral anti hyperglycemic drug used by the patients of diabetes all over the world. In present study, Metformin hydrochloride (Glucophage) was used to determine the histological changes in liver of mice. Twenty mice (4-5 weeks old) were given oral gavages of 0.1 ml of 0.00, 31.25, 125 and 500μg/g B.W (Complete). of Metformin prepared in distilled water, for 04 weeks daily. After 24 hours of last dose, the animals were anaesthetized torecoverliver tissues following fixation in Bouin’s fluid and processing for histological preparation using different grades of alcohol and xylene for dehydration. These tissues were later on infiltrated with paraffin wax, sectioned to size of 4μm and stained with Hematoxylin and Eosin. The histological analysis revealed that metformin could cause adverse malformations like pyknosis, necrosis, and steatosis.