Metformin is one of the medications used to treat diabetes most frequently nowadays, which is also used in non-diabetic patients to treat fatty liver, weight reduction, infertility, polycystic ovarian syndrome, prevention of pregnancy complications, prevention of diabetes and obesity. However, its use may have several serious adverse effects such as hepatic injury, renal toxicity and spleen damage. This study was designed to assess the potential pathogenic impact of metformin on the liver, kidneys and spleen in normoglycemic rats. Two equal groups of twelve adult female rats were randomly selected. First group was intraperitoneally injected with metformin (200 mg/kg) as a single dose for three days and the second group was used as a control received an intraperitoneal injection of the similar-volume of physiological saline. The animal weight, organs weight, creatinine, lactate and vitamin B12 were measured. Histopathological changes in the liver, kidneys and spleen were also studied. The blood parameters levels didn't alter with metformin use. The metformin treated group showed structural damage of varying degrees in all three organs; liver, kidney and spleen. Metformin like any medication may be helpful in treating certain medical issues. However, the results of the current study confirms that the metformin use can cause hepatic injury, renal toxicity and moderate damage to the spleen tissues, which may contribute to the clinical effects of the drug; physicians and patients alike need to be aware of these possible side effects.