Abstract A systematic review of randomized controlled clinical trials of nonsteroidal antiinflammatory drugs (NSAIDs) in rheumatoid arthritis (RA) patients was conducted to evaluate the risk of NSAID-induced adverse reactions. Double-blind, randomized, controlled trials with 6-week treatments for RA patients were included in the study. The endpoints for the analysis included any adverse reactions, digestive adverse reactions, and upper gastrointestinal (GI) adverse reactions. A fixed-effect model was used for estimation of the risk. Time-to-event analysis of the incidence of adverse reactions was also conducted. A total of 28 trials was included for the analysis, and a total of 30 NSAIDs were used in the trials. The proportion of patients who experienced any adverse reaction was as follows: piroxicam 18.9% (3 trials), diclofenac 18.8% (4 trials), indomethacin 22.1% (14 trials), and aspirin 25.0% (4 trials). The proportion of patients who experienced digestive adverse reactions was as follows: piroxicam 10.2%, diclofenac 10.6%, indomethacin 13.1%, and aspirin 14.1%. Most withdrawals due to adverse reaction occurred during the first 3 weeks after administration of the NSAID. Although the risk of NSAID-induced adverse reaction was different from drug to drug, the risk of adverse reaction was clinically significant.