One of the most frequently asked questions about the drugs used after transplantation to prevent rejection concerns the physical changes that can be seen with high-dose or long-term use of steroids or glucocorticoids . Steroids are substances made by the body for a large number of important processes. Sex steroids such as estrogen or progesterone are used in a variety of conditions to regulate sexual functioning. Male sex hormones (androgens) are used and abused by athletes to enhance performance and muscle development.

The drugs used after transplantation are steroids called corticosteroids (glucocorticoids). Corticosteroids regulate many metabolic processes including the immune system. That is why they are so widely used for medical conditions such as severe types of arthritis, asthma or systemic lupus erythematosus. Many people have seen others with the "moon-face" that is present with excess amounts of corticosteroids. The most obvious physical changes seen in folks who either produce too much corticosteroids on their own (Cushing's Syndrome) or are taking large amounts to treat some severe medical condition are weight gain, moon-face, and fat deposits on the chest, abdomen and back (called a "buffalo hump"). There are many other severe drawbacks to using corticosteroids that are not as obvious on first glance.

Since corticosteroids are so important in the functioning of many body systems, too much can have wide spread side-effects.