For patients with diabetic ketoacidosis, urine is often prone to a rotten apple odor. Because in diabetic ketoacidosis patients, due to glucose utilization disorder, fat decomposition will lead to an increase in ketone bodies, and ultimately converted to acetone from the urinary excretion, and acetone itself is characterized by the presence of rotting apple flavor such as the smell. So if the patient’s urine smells like rotten apples, it is highly suggestive that the patient’s urine contains acetone, thus inferring the possibility of diabetic ketoacidosis in the patient. If the patient’s urine ketone bodies (++++). At the same time the whole blood sugar is obviously high, can be diagnosed as diabetic ketoacidosis, this time it is necessary to test blood gas analysis, to assess whether the patient is the existence of acidosis.