Cat's claw is thought to have anti-inflammatory effects and has been used for rheumatoid arthritis and osteoarthritis. Compounds in cat's claw are thought to block the body's production of inflammation-producing substances called prostaglandins and tumor necrosis factor (TNF). Cat's claw is believed to reduce pain somewhat, but it doesn't appear to have much of an effect on reducing swelling. More evidence is needed before cat's claw can be used as a treatment for arthritis.