Odontogenic sinusitis generally refers to odontogenic maxillary sinusitis, which is caused by odontogenic infections and other causes, and can be treated with anti-infective medications such as cefaclor; it can also be treated surgically if needed, such as enlargement of the natural orifice of the maxillary sinus for drainage. Most of the odontogenic maxillary sinusitis is caused by pulp infection resulting in pulpitis, odontogenic abscess and severe periapical disease, which is categorized into acute and chronic odontogenic maxillary sinusitis. In the acute stage, patients can apply localized hot compresses and contract mucosal swelling through nasal drops of 1% ephedrine to facilitate drainage. If the drainage of pus is not smooth and the symptoms are not reduced, puncture irrigation can be used. For teeth that cannot be retained, they can also be extracted and drained. Antibiotics, such as cefaclor, need to be applied during treatment according to the pathogenic bacteria (anaerobic, aerobic mostly streptococcus). The chronic phase can be treated conservatively, either by using vasoconstrictors through the nose to allow sinus drainage, or by using maxillary sinus lavage to treat the source tooth, extracting or removing the broken root and removing the lesion. If necessary, surgical treatment can be done by performing an enlarged drainage of the natural orifice of the maxillary sinus. After the inflammation is controlled, then do the repair of oral maxillary sinus fistula. It is recommended that patients seek timely medical treatment to clarify the diagnosis and condition, and follow the doctor’s instructions to standardize the use of medication and treatment.