The aim of the present work was to study the in vivo anti-inflammatory activity of six NSAIDs, ibuprofen, diclofenac, nimesulide, meloxicam, celecoxib and rofecoxib, using the rat air-pouch model of inflammation to characterize the ability of these drugs to induce gastric damage and PGE2 inhibition. Selective compounds were observed to have no ulcerogenic properties at antiinflammatory doses; however, these drugs were weaker inhibitors of several inflammatory aspects such as cell influx and exudate formation. In contrast, the non-selective and preferential compounds present anti-inflammatory properties at lower doses than presented by selective drugs. At antiinflammatory doses, only meloxicam and ibuprofen produced gastric damage and inhibition of PGE 2 synthesis, suggesting that ulcerogenic properties of NSAIDs cannot be predicted by their selectivity index, since meloxicam demonstrates ulcerogenic properties despite its preferential profile. © VSP 2005.