Corticosteroids are used to treat autoimmune disorders, swelling, and allergies, among many other conditions. Corticosteroids generally work by reducing inflammation and suppressing the activity of the immune system. These medications come in several different forms, including oral pills, injections, inhalers, nasal sprays, and more. Common examples include prednisone (Rayos), triamcinolone (Kenalog-10), budesonide (Pulmicort Flexhaler, Pulmicort Respules), and fluticasone (Flonase).