What is the difference between a corticosteroid and an anabolic steroid?

Both corticosteroids and anabolic steroids are sometimes just called steroids. However, corticosteroids are very different from anabolic steroids. Corticosteroids reduce the swelling in the airways that make breathing difficult and also reduce the amount of mucus produced in the lungs. Anabolic steroids have an effect similar to that of the male hormone testosterone, and are used illegally by some athletes to increase muscle mass, strength and endurance. Corticosteroids do not have these effects.