Hyalgan Injection contains Hyaluronic Acid 20 mg, a naturally occurring glycosaminoglycan found in the synovial fluid of joints, which serves as a lubricant and shock absorber. It is indicated for the treatment of pain associated with osteoarthritis of the knee in patients who have not responded adequately to conservative non-pharmacologic therapy and simple analgesics such as acetaminophen. The intra-articular administration of Hyalgan helps restore the viscoelastic properties of synovial fluid, thereby improving joint mobility and reducing pain. The product is typically administered as a series of weekly injections directly into the affected knee joint, with the treatment course usually consisting of five injections. Hyaluronic Acid in Hyalgan acts by supplementing the deficient or degraded endogenous hyaluronate in osteoarthritic joints, promoting lubrication, cushioning, and protection of articular cartilage. Clinical studies have demonstrated its efficacy in reducing pain and improving joint function, with a favorable safety profile. Common adverse effects may include transient injection site pain, swelling, or effusion. Hyalgan Injection should be used under medical supervision, with aseptic technique to minimize the risk of infection. It is contraindicated in patients with hypersensitivity to hyaluronic acid or avian proteins.