Bleeding gums may be caused by periodontitis, which can be diagnosed through periodontal tissue examination, and blood in sputum may be caused by bronchial diseases, which can be diagnosed through CT, bronchoscopy, etc. The details are as follows. 1. Bleeding gums: Through periodontal tissue examination, plaque and tartar can be seen on the surface of the teeth by visual inspection, the gums are bright red or deep red in color, soft and swollen in texture, bleeding by probing, and there is loss of attachment, which can be basically diagnosed as periodontitis. 2. Blood in sputum: Bronchial diseases such as bronchial dilatation, bronchial tuberculosis, bronchopulmonary tumors and so on may lead to blood in sputum, which can be clearly diagnosed by CT and bronchoscopy. When you find blood in the mouth, it is difficult to accurately determine whether the bleeding comes from the gums or blood in sputum, so it is recommended that you go to the hospital in time to clarify the cause of the disease and then carry out targeted treatment.