If you have a cold with blood in sputum, you should first consider that it is caused by respiratory diseases, such as acute tonsillitis or severe pharyngitis, because the local mucous membrane is congested and edematous, which can lead to the rupture of the local mucous membrane when coughing and the phenomenon of blood in sputum occurs. If the patient secondary bacterial cold can occur in the lower respiratory tract infection, such as bronchitis, pneumonia, due to respiratory tract infection can sometimes appear a little sputum with blood symptoms, especially when the patient in the violent coughing is likely to lead to local bleeding aggravated. Some patients have chronic underlying lung diseases, such as bronchiectasis, chronic obstructive pulmonary disease, interstitial lung disease, or chronic cardiac insufficiency, which may lead to the aggravation of their condition when they have a cold and manifest as the phenomenon of blood in sputum. Therefore, blood in sputum in a cold should be perfected by blood routine, chest CT, and throat examination in order to determine the cause of the disease.