Untreated diabetes mellitus combined with tuberculosis may cause patients to drink more, urinate more, lose weight, itchy skin, cough, hemoptysis and other symptoms, and in serious cases, lead to diabetic nephropathy, pneumothorax, respiratory failure and other complications. It is recommended to go to the hospital in time for examination and treatment. Diabetes mellitus is a metabolic disease, and its typical symptoms are “three more and one less”, i.e., more drinking, more eating, more urination, weight loss, which may be accompanied by itching and other symptoms. With timely and effective treatment, complications can be delayed to a great extent. However, if diabetes is not treated in time, long-term metabolic disorders of carbohydrates, fats, and proteins can cause a variety of chronic complications, such as chronic lesions of the kidneys, heart, blood vessels, and other tissues and organs, and in severe cases, can also lead to acute and severe metabolic disorders, such as diabetic ketoacidosis, and so on. Tuberculosis is a respiratory infectious disease, mostly chronic process, manifested as coughing, coughing sputum, hemoptysis, etc., may be accompanied by fever, night sweats and other systemic symptoms, after early diagnosis, treatment, most of the prognosis is good. Patients can develop chronic pulmonary heart disease and heart failure in later stages, which can lead to death due to delayed treatment. Diabetes mellitus combined with tuberculosis without treatment, can be simultaneous multi-organ dysfunction, failure, seriously affect the patient’s life treatment and survival time. Patients diagnosed with diabetes and tuberculosis should consult a doctor promptly and actively cooperate with the doctor’s treatment.