Sinusitis with a foul odor in the nose may be due to the presence of anaerobic infections, purulent secretions remaining in the nasal cavity, nasal polyps and so on. 1. Sinusitis is an inflammatory disease of the sinus mucosa, often secondary to rhinitis and upper respiratory tract infections, the causative organisms are mostly purulent cocci, and when combined with anaerobic infections, it can emit a foul odor. 2. Local inflammation produces purulent secretion. A large amount of purulent secretion in the nasal cavity is difficult to wipe out, and when it remains in the nasal cavity, it can also lead to odor. Especially in the case of odontogenic maxillary sinusitis, the secretion is not easy to be discharged, which is more likely to lead to a fishy odor. 3. When sinusitis repeated episodes, stimulate the nasal mucosa pathological hyperplasia, resulting in nasal polyps, further aggravate the nasal drainage obstacles, nasal odor. Specific causes are recommended to consult a doctor in a timely manner, by a professional doctor to find out the cause of the disease and the condition of the clear.