Diclofenac sodium topical gel is a nonsteroidal anti-inflammatory drug (NSAID) that is used to relieve joint pain from arthritis. It belongs to a group of medications called NSAIDs, which work by stopping the bodys production of a substance that causes pain. The gel is applied to the skin and is used to relieve pain from arthritis in certain joints such as those of the knees, ankles, feet, elbows, wrists, and hands. It is also used to treat pain and swelling caused by osteoarthritis of the knees. In addition, diclofenac topical 3% gel is used to treat actinic keratosis, a skin problem that may become cancerous if not treated. However, it is important to note that diclofenac sodium topical gel does not cure arthritis and will help only as long as it is used.