Chronic alcoholism is a frequently unrecognised cause of ketoacidosis. Most patients with alcoholic ketoacidosis present with normal or low glucose, but this condition can present with hyperglycaemia. This can lead to misdiagnosis of diabetes ketoacidosis and, therefore, inappropriate treatment with insulin. We describe a 37-year-old Caucasian woman with chronic pancreatitis secondary to excess alcohol consumption, admitted with abdominal pain and vomiting, fulfilling the criteria for diabetes ketoacidosis. She was treated according to diabetes ketoacidosis protocol and experienced a hypoglycaemic attack within an hour of initiation of insulin. On review of her history, she was found to have three similar episodes over the past 12 months. Alcoholic ketoacidosis can present with hyperglycaemia due to relative deficiency of insulin and relative surplus in counter-regulatory stress hormones including glucagon. Awareness of the syndrome with a detailed history helps to differentiate alcohol ketoacidosis from diabetes ketoacidosis and prevent iatrogenic hypoglycaemia.