ABSTRACT
Metformin is a biguanide oral hypoglycemic agent commonly used in the treatment of diabetes mellitus. Metfofmin is excreated largely by the kidney and binds only negligibly to plasma proteins. Toxicity is usually seen when metformin is prescribed to patients with renal insufficiency. Lactic acidosis in diabetics on metformin therapy is rare but still associated with poor prognosis. For an early diagnosis, clinical symptoms of intoxication should be well known by physicians and patients. First-line therapy for correction of lactic acidosis and effective elimination of metformin is bicarbonate hemodialysis. We report a case of acute renal failure due to metformin-associated lactic acidosis in elderly type 2 diabetes mellitus patient and she was successfully treated by hemodialysis with bicarbonate buffer.