Cough with blood in the sputum is a common symptom of the respiratory system, and there are many diseases that can cause this phenomenon. It should also be noted that a small number of patients can also show blood in sputum due to nasal diseases and gum disorders. For patients over 40 years old who have been smoking for a long time, if they repeatedly have blood in their sputum, they should pay attention to it and pay attention to the possibility of excluding lung cancer. Therefore, when there is blood in sputum, you should actively come to the hospital, improve the relevant examination, and deal with the cause of the disease.