Prednisone is a corticosteroid medication commonly used to reduce inflammation and suppress the immune system. It is prescribed to treat a wide range of conditions, including autoimmune diseases like lupus and rheumatoid arthritis, allergic reactions, asthma, and certain types of cancer. Prednisone works by mimicking the effects of cortisol, a natural hormone produced by the adrenal glands, helping to decrease swelling, redness, and immune activity.