Diabetic patients with rotten apple taste in the mouth may be caused by diabetic ketoacidosis, at this time should promptly seek medical attention, as soon as possible rehydration in order to restore blood volume, correct the state of water loss, lowering blood glucose, correcting the electrolyte and acid-base balance imbalance, and at the same time, actively search for and eliminate the causative factors, prevention and treatment of complications. Rehydration is a key part of treatment. Only after the effective tissue perfusion is improved and restored can the biological effect of insulin be brought into full play. The basic principle is “fast then slow, salt then sugar”. At the same time, small-dose (short-acting) insulin treatment program can be given. During the rescue process, attention should be paid to the coordination of treatment measures and the prevention and treatment of important complications from the beginning, especially cerebral edema and renal failure, to maintain the function of important organs. If diabetic patients appear in the mouth rotten apple flavor, it is recommended to seek medical attention in time, under the guidance of the doctor, improve the relevant examination, clarify the cause of the disease, and target treatment.