Hydrocortisone Sodium Injection is used to treat various conditions such as arthritisallergies, blood diseases, breathing problems, certain cancers, eyediseases, intestinal disorders, and skin diseases. It weakens your immune system response to various diseases to reduce symptoms such as swelling and allergic-type reactions. Hydrocortisone may also be used with other medications to replace certain hormones if you have decreased adrenal gland function or Addison disease. Hydrocortisone belongs to a class of drugs known as corticosteroids.