No, Xolair is not a steroid, but it does prevent inflammation. Xolair works by preventing IgE from binding to IgE receptors on mast cells and basophils, preventing the release of chemicals such as histamine, and reducing the number of IgE receptors on basophils. Histamine can cause inflammation and symptoms such as difficulty breathing (wheezing), a runny nose, watery eyes, tissue swelling, itchy skin, and hives. Xolair belongs to the class of medicines known as monoclonal antibodies. It may also be called a selective immunosuppressant.

Steroids, such as prednisone, prevent inflammation by mimicking the actions of cortisol, which is a naturally occurring hormone that is released by the adrenal glands.

Xolair (omalizumab) may be used to treat moderate-to-severe, persistent, allergic asthma that is not adequately controlled by inhaled corticosteroids in adults and children aged 6 and over who have had a positive skin test to an allergen or who react to an allergen that is present in their environment year-round.