Turning on the air conditioner and having a nosebleed can be useful if the nosebleed is caused by dryness, using a humidifier. However, nosebleeds can also be caused by diseases such as nasal hemangioma, nasopharyngeal cancer, nasopharyngeal fibroangioma, etc. It is recommended to go to the hospital to find out the cause of the disease before treatment. Air conditioners produce a large amount of condensation when cooling, which dries out the air in the room. Prolonged exposure to such an environment will cause the nasal mucosa to lose moisture and produce fissures, leading to capillary rupture and bleeding. When using air conditioning, using a humidifier in the air-conditioned room can increase the humidity of the room, to a certain extent, to prevent nosebleeds. Rhinitis, trauma, intranasal vascular lesions or tumors may also cause nosebleeds. Therefore, when there are frequent nosebleeds or large amounts of persistent bleeding phenomenon, we should be alert to nasal hemangioma, nasopharyngeal carcinoma, nasopharyngeal fibroangioma and other diseases, it is recommended to go to the regular hospital as soon as possible to check, investigate the cause of the disease, and actively treatment.