The syndrome differentiation of the disease should aim at the predominance of yin deficiency or drynessheat. Generally at the onset, yin deficiency predominates. As the disease progresses, there appears the coexistence of yin deficiency and dryness-heat, and yin deficiency predominates again at the late stage. Clinically, the disease is classified as the following syndromes: fluid consumption due to lung heat, excessive fire in the stomach, deficiency of kidney yin, deficiency of both qi and yin, and deficiency of both yin and yang.

The treatment is based on the principle of eliminating heat by nourishing yin, moistening dryness and promoting fluid production. According to the condition of the principal and secondary aspects, deficiency and excess, as well as the location of pathological changes of the disease, the following methods are respectively adopted: clearing heat and purging fire, resolving phlegm to activate meridians, promoting blood circulation to remove blood stasis, removing dampness, nourishing the kidney to replenish yin, invigorating the spleen to tonify qi, replenishing both yin and yang, etc.

Essentials for TCM Diagnosis 
(1) The onset of the disease is slow and the patients are mostly of middle and old age or have the family history of the disease.

(2) Polydipsia, polyphagia, polyuria, emaciation, and weakness. There may also be pruritus vuluae or pruritus cutanea, numbness of limbs, sensory disturbance of extremities, blurred vision, lumbago, hyposexuality, irregular menstruation, impotence, sterility, etc.

(3) Laboratory examination reveals fasting bloodglucose>7.0 mmol/L, or blood-glucose two hours after meal>11.1 mmol/L, decrease of sugar tolerance, fasting urine sugar positive over three times in succession.

(4) Insulin determination, insulin release test, serum c-peptide determination, glycosylized hemoglobin determination, ketonuria test, and urinometry are helpful to the diagnosis of the disease.