Diabetes is an endocrine and metabolic disease caused by a variety of causes,which belongs to the category of “consumptive thirst” in traditional Chinese medicine(TCM).Coming from Treatise on Cold Pathogenic and Miscellaneous Diseases,Dachaihu Decoction is a formula for relieving both superficial and internal disorders.Modern research shows that clinical application of Dachaihu Decoction can treat metabolic diseases such as diabetes,and can achieve significant curative effects.In addition,this paper introduces Professor NI Qing's typical medical case of using Dachaihu Decoction.Mr.NI's treatment of diabetes is not limited to the traditional “three elimination syndrome differentiation” diagnosis and treatment model,but is a combination of disease and syndrome based on syndrome differentiation,and at the same time,adjusts the patient's diet and obtains the exact effect,which can hopefully provide ideas for the clinical application of TCM in the treatment of diabetes.