BACKGROUND: Selective cyclooxygenase-2 (COX-2) inhibitors are widely used. They have no advantages in terms of efficacy, and it is not documented that they cause fewer adverse effects than conventional NSAIDs. MATERIAL AND METHODS: The adverse effects of rofecoxib, celecoxib and other NSAIDs are reviewed. Relevant literature was identified on Medline and in the reference lists in key articles. RESULTS: Rofecoxib and the novel COX-2 inhibitors etoricoxib and valdecoxib have a higher degree of COX-2 selectivity than traditional NSAIDs. Celecoxib is less COX-2 selective and appears to be similar to diclofenac. Rofecoxib induces thromboembolic adverse effects more frequently than conventional NSAIDs. INTERPRETATION: The cardiovascular problems conferred by rofecoxib are probably a class effect and thus inducible by other selective COX-2 inhibitors. Pending comprehensive safety data, caution is warranted regarding the use of these drugs.