In ENT clinics, we often encounter patients with nasal discomfort who describe themselves as having sinusitis or ask the doctor to check whether they have sinusitis. This shows that sinusitis is a very common ENT disease with a high incidence in both adults and children. Sinusitis is a chronic purulent inflammation of the mucous membrane of the sinuses, which can be divided into acute and chronic, with chronic being more common. Acute sinusitis is mostly caused by upper respiratory tract infection, and its symptoms are more obvious, such as nasal congestion, headache, runny nose, mainly clear snot, which can gradually become sticky, with few systemic symptoms such as elevated body temperature, and the symptoms can be significantly reduced in about 3 to 5 days. However, severe sinusitis should not be ignored, especially in young children who have a “cold” and should be treated early to prevent blockage of the eustachian tube, which can lead to hearing loss due to the inability to remove fluid from the middle ear. Chronic sinusitis is often caused by acute purulent sinusitis that has not been treated in a timely and reasonable manner. Other causes are similar to acute suppurative sinusitis, with infection, allergic rhinitis, and sinus drainage disorders being the main causes. Odontogenic maxillary sinusitis can also cause chronic sinusitis. The three typical symptoms are “nasal congestion, runny nose and headache”. In addition, chronic cough caused by backflow of nasal secretions into the pharynx, cold symptoms throughout the year, fishy smell in the nose, fever, facial pain, and thick, yellowish-green or red nasal discharge are all common symptoms. Also, long-term runny, blowing nasal cavity and poorly ventilated nasal cavity often make people drowsy, making people listless, depressed, memory loss, affecting work and life. Reminder: If you often have a cold or cold for a long time, it is best to seek immediate medical attention to avoid the development of acute rhinitis into acute sinusitis, or even into chronic sinusitis.