Nasal polyps are non-cancerous growths that develop in the nasal passages and sinuses. They are common in adults and more frequent in men. Nasal polyps can be caused by viral or bacterial infections, allergies, asthma, or chronic inflammation. They may cause symptoms like nasal obstruction, loss of smell, and mouth breathing. Complications can include sleep apnea or bleeding. Treatment involves nasal steroids, nasal irrigation, and sometimes surgery to remove the polyps. Surgical removal provides relief from nasal obstruction but polyps may return over time.