Pus flowing from the nostrils is definitely an acute purulent infection or a chronic purulent infection of the nasal cavity and sinuses. There are several common ones, the first one, acute and chronic sinusitis, mainly maxillary sinusitis or sieve sinusitis. There is a lot of purulent nasal discharge, facial pain and even head swelling, headache and fever. The second kind, pus nasal discharge is mostly nasal foreign body, especially in children. The nasal foreign body stays in the nasal cavity for a long time, and the spontaneous bacterial infection stimulates the surrounding nasal muscle tissue, and it leads to infection, so that there is a large amount of pus nasal discharge, and the foul smell in the nasal cavity is very serious. The spontaneous infection of some tumors can also cause the situation of pus nasal discharge in the nasal cavity. In short, pus flow is evidence of the presence of infection.