A 74 year old woman was admitted to hospital for obnubilation and anuria after presenting for 5 days with abdominal pain and vomiting. Her history included DM treated with metformin (850 mg/8 h) and glibenclamide. Blood pressure was 105/60 mmHg, heart rate was 155 beats/minute and temperature 36.7ºC. Examination revealed severe dehydration, disorientation, Kussmaul's respiration, abdominal pain with weak peristalsis and absence of abdominal defence. Table 2 shows the main analytical data, highlighting in addition a hyperamylasaemia of 2,605 U/l. An abdominal CT scan revealed an enlarged pancreatic head suggestive of acute pancreatitis. After discontinuation of metformin administration, the patient was intubated orotracheally and connected to a mechanical ventilator. She also received fluid therapy with potassium supplementation, noradrenaline, bicarbonate, insulin, amiodarone, imipen and furosemide. On the second day of admission, after administering 750 mEq of bicarbonate and 140 mEq of potassium, acid-base balance (pH 7.41 and bicarbonate 20 mEq/l) and water-electrolyte balance (sodium 147 mEq/l, potassium 3.5 mEq/l) normalised and creatinine decreased to 5.5 mg/dl. On the third day of admission, due to the presence of repeated mucous stools, a colonoscopy was performed which revealed a sessile polypoid formation located next to the anal sphincter and measuring 14 cm in length. The endoscopic specimen was reported as a villous adenoma of the rectum. On the seventh day of admission the patient was extubated, and two days later she was transferred to the ward for removal of the adenoma.