The nutritional supplements glucosamine and chondroitine sulphate are widely used in the treatment of osteoarthritis. In published studies, glucosamine used in a dosage of 1.5 gram daily is, after a period of 2 to 4 weeks, just as effective as low doses of NSAIDs in alleviating pain. Chondroitine sulphate has been less well investigated. There are indications that it affects the symptoms of osteoarthritis, even though this effect only occurs after a longer period of time. The side effects for both substances are minor. A disease-modifying effect (defined as delay of radiological progression of osteoarthritis) has not been proven.