Children with nose bleeding on the left side of the nose may suffer from diseases such as deviated nasal septum, nasal hemangioma, allergic rhinitis, blood system diseases, and so on. 1. Deviated nasal septum: If the nasal septum is deviated to the left side, it will lead to the mucous membrane tension and thickness of the mucous membrane become larger and smaller, and the front of the nasal septum is rich in capillaries, which will easily cause the damage of the capillaries here, which will be manifested as bleeding from the left side of the nose. 2. Nasal hemangioma: if there is a hemangioma in the left nasal cavity of children, when this area is hit by trauma, it will easily lead to rupture of the tumor, which will be manifested as bleeding from the nostril on the affected side. 3. Allergic rhinitis: if the child inhales smoke, mites and other allergens, the sensitizing substances can easily invade the mucous membrane of the nasal cavity, resulting in capillary expansion and congestion, brittleness increase, if the patient blows his nose with force, the mucous membrane of the nasal cavity is ruptured, which leads to nosebleed, often accompanied by nasal congestion, itchy nose and other uncomfortable symptoms. 4. Blood system diseases: for example, leukemia, lymphoma, myeloma, etc., can cause the body’s coagulation dysfunction or reduced platelet production, resulting in spontaneous bleeding, nose bleeding. In conclusion, children bleeding from the left side of the nose, must be vigilant, if accompanied by other uncomfortable symptoms, it is recommended to seek medical attention in a timely manner. The left side of the nose bleeding children may also have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.