The incidence of diabetes is increasing, presenting a number of challenges to the peri-operative physician. Sodium-glucose co-transporter-2 (SGLT2) inhibitors are licensed for use in diabetes, chronic kidney disease, and heart failure. A rare, but serious, side effect is euglycaemic diabetic ketoacidosis in which patients have raised blood ketones and acidosis but normal, or near normal, blood sugar levels, making diagnosis difficult. Risk factors for EDKA include starvation, stress response to surgery, and acute illness. National guidance states that patients should have their SGLT2i stopped 48 hours pre-operatively and that blood ketones should be checked at least daily.