It's not called "stinging nettle" for nothing: if you're going to spend time in a nettle patch, cover up. The hairs on nettle's leaves and stems are miniature hypodermics, waiting to pucture your skin, which - ouch! - stings, then burns, then aches. But on arthritic joints, that sting stimulates, then exhausts, the production of pain messengers to the brain. Nettle leaf soup (cooking neutralizes the sting) has been found to reduce pain and immobility in people suffering from rheumatoid arthritis.