Diabetic ketoacidosis (DKA) is a severe and life-threatening metabolic disease caused by an absolute or relative deficiency of insulin in the body, usually affecting middle-aged cats and dogs. The presentation aims to introduce DKA and emphasize the importance of early detection, as it requires intensive in-hospital treatment and early diagnosis and monitoring are important for healing or preventing the condition. Symptoms include vomiting, increased urination and thirst with normal appetite, decreased alertness, and dehydration.