While effective drugs are available to deal with the symptoms and modify the progress of osteoarthritis and rheumatoid arthritis, these may cause serious adverse events and not all patients will obtain relief. Many people with these diseases use complementary medicines.This article presents an overview of the evidence for the most promising complementary therapies for osteoarthritis and rheumatoid arthritis, with other information that general practitioners need to know.There is reasonable evidence to support the use of glucosamine, avocado/soybean unsaponifiables and chondroitin in osteoarthritis, and omega-3 fatty acids and gammalinolenic acid in rheumatoid arthritis. However, no current evidence does not equate to lack of effectiveness. Rigorous research into the use of complementary medicines in arthritis is evolving and many of the systematic reviews used in preparation of this article are being updated every few years to incorporate new trial evidence as it becomes available.