The use of non steroidal anti-inflammatory drugs (NSAIDs) is tempered by the development of side effects primarily in the gastro-intestinal tract. These effects result mainly from inhibition of the enzyme cyclo-oxygenase (COX)-1. Two NSAIDs (celecoxib and rofecoxib) COX-2 specific inhibitors had considerably lower ulcerogenic rates and lower serious gastro-intestinal side effects when compared with other NSAIDs used in rheumatoid arthritis and osteoarthritis. However, the exact place of COX-2 specific inhibitors remain to be determined as compared with the association of other NSAIDs and proton-pump inhibitors in the elderly. The efficacy of COX-2 specific inhibitors in digestive tumors is still unclear.