The left nostril always bleeds, clinically, the main consideration is that there are the following possibilities: 1, nasal arterial hemorrhage, this situation is mainly due to the rupture of the arteries in the nasal cavity caused by recurrent bleeding, the reason may be the dryness of the mucous membrane of the nasal cavity, the patient has hypertension, arteriosclerosis and other medical history. Clinically, it is mainly recommended that patients go to ENT department to do nasal filling to stop bleeding, or endoscopic electrocoagulation to stop bleeding; 2, there are benign tumors in the nasal cavity, common nasal hemorrhagic polyps, and nasal hemangioma. This situation once diagnosed, are recommended for surgical treatment. There are also malignant tumors in the nasal cavity, such as nasal maxillary sinus cancer and sieve sinus cancer. Bleeding in this case is also recommended to be treated by surgery or postoperative radiotherapy.3. Individual patients, such as young people, who have nasal cavity and nasopharyngeal fibrous hemangioma, will also bleed repeatedly. For the above cases, it is recommended that patients go to the ENT department for nasal endoscopy, and check sinus CT and other tests if necessary.