Azelastine is a medication primarily used to treat allergic rhinitis, which is inflammation of the nasal passages due to allergies. It works as an antihistamine, blocking the action of histamine, a substance in the body that causes allergy symptoms like sneezing, runny nose, and itching. Azelastine is available in various forms, including nasal sprays and eye drops. In addition to treating allergies, azelastine can also help relieve symptoms of conjunctivitis, an eye condition often caused by allergies. It is generally well-tolerated, but some users may experience side effects such as drowsiness or a bitter taste. Always consult a healthcare professional before use.