Olfen 10 mg/g Gel 1x100 g is a topical gel containing diclofenac, a nonsteroidal anti-inflammatory drug (NSAID). It is used to relieve pain and inflammation associated with musculoskeletal conditions, such as sprains, strains, arthritis, and back pain. The gel is applied directly to the skin, where it works locally to reduce swelling and alleviate pain.