An important group of non steroidal antinflammatory drugs (NSAIDs), which have been used for the symptomatic treatment of various forms of arthritis, are the 2-arylpropionic acid derivatives, 'profens'. By virtue of a chiral carbon atom on the propionic acid side chain, they exist as enantiomeric pairs. Whereas the S (+) enantiomer could be represented as an effective, but unselective COX inhibitor, the R (-) enantiomer could be much less active in this respect. However, recent findings suggest that certain pharmacological effects of profens cannot be attributed exclusively to the S (+) enantiomer. To obtain further insights into the pharmacological effects of profens, this study investigated the influence of pure enantiomers (S), (R), and racemic flurbiprofen and ketoprofen on the production of NO, MMP-3, PGE(2), ROS and GAGs, key molecules involved in cartilage destruction. Our results show that (S) flurbiprofen and ketoprofen decrease, at 1- and 10-microM concentrations, the interleukin-1beta induced cartilage destruction.