Of all rheumatic diseases, osteoarthritis (OA) and rheumatoid arthritis (RA) are the most frequently occurring. Although they differ in pathophysiology and the molecular mechanisms responsible for the destruction of cartilage (since RA is an inflammatory disease and OA is not), there are, however, a certain number of similarities and common pathways in the inflammatory processes of both diseases: mild inflammatory phenomena have been observed during OA, and both interleukin-1 and tumour necrosis factor-alpha seem to play key roles, as in RA. Although there is a dramatic difference between the 2 diseases in the intensity of inflammation, the inflammatory process is responsible for the synthesis of metalloproteinases and free oxygen radicals, and, subsequently, for progressive cartilage destruction. Both OA and RA engender important costs for the healthcare system. Direct costs result from practitioner visits, drug purchase and management, drug-related adverse effects, management or hospital care; indirect costs are linked to progressive functional disability. Although RA leads to significant individual costs, OA is more problematical for the healthcare system, since its prevalence is far higher than that of RA. Thus, rheumatic diseases have become a major public health problem. Optimal therapeutic strategies need to be determined in order to define the most effective procedure for controlling disease symptoms such as pain, stopping or slowing down disease progression and, finally, keeping patients active. But it is of paramount importance that the gain in efficacy be associated with a gain in drug safety.