Runny nose and bleeding may be caused by mucous membrane rupture in the nasal cavity, neoplastic rupture in the nasal cavity, malignant tumor, etc., as follows: First, mucous membrane rupture in the nasal cavity: mostly seen in acute rhinitis, allergic rhinitis, patients repeatedly blow their noses for a long time, due to artificial factors stimulation, easily lead to local rupture and erosion of the mucous membrane of the nasal septum and the mucous membrane of the inferior turbinate, thus appearing bleeding, which is also clinically more blood in nasal mucus This is also the reason why blood in the nose is more common in clinical practice. Secondly, neoplastic breakage in nasal cavity: some patients have neoplastic nasal cavity, and the neoplastic local breakage can lead to blood in the nose, such as patients with nasal sinus involute papilloma, nasal bleeding polyp, septal sinus cancer, maxillary sinus cancer, olfactory neuroblastoma and other related cases. For the above-mentioned cases, surgery may be clinically necessary. Thirdly, malignant tumor: some patients have malignant tumor in nasopharynx, commonly there is nasopharyngeal carcinoma which can be manifested as blood in snot, clinically it is mostly manifested as blood in retracted snot. For this situation, clinical vigilance is needed. In short, blood in the runny nose needs to go to ENT department to perfect nasal endoscopy, and at the same time combine with sinus CT and other related examinations to determine the cause of this situation.