Americans spend more on natural remedies for osteoarthritis than for any other medical condition. In treating osteoarthritis, glucosamine and chondroitin sulfate, two of the molecular building blocks found in articular cartilage, are the most commonly used alternative supplements. In randomized trials of variable quality, these compounds show efficacy in reducing symptoms, but neither has been shown to arrest progression of the disease or regenerate damaged cartilage. Although few clinical trials on S-adenosylmethionine exist, preliminary evidence indicates that it relieves pain to a degree similar to that of nonsteroidal anti-inflammatory drugs but with fewer side effects. Clinical trials of dimethyl sulfoxide offer conflicting results. Neither ginger nor cetyl myristoleate has proven clinical usefulness.