Xolair 150mg Injection is a monoclonal antibody used to treat allergic asthma, chronic rhinosinusitis with nasal polyps, and chronic spontaneous urticaria. It works by targeting and neutralizing immunoglobulin E (IgE), a primary antibody responsible for initiating allergic reactions. Common side effects may include joint pain, dizziness, stomach discomfort, headaches, ear pain, and reactions at the injection site, such as pain, swelling, itching, and redness. It is not recommended for use in children under the age of 6.