This review describes the tolerability profile of nimesulide as documented in a global assessment of the clinical data available to Helsinn for this drug. Data from 151 trials were considered and the relevant case report forms and study reports were used as source information. The analysis was conducted using between-treatment and within-treatment comparisons. The between-treatment comparison included data derived from placebo-controlled trials, while the within-treatment comparison included nimesulide data only. Of 4945 subjects treated with nimesulide, 349 (7.1%) experienced adverse events and 52 (1.1%) withdrew from treatment. The most frequently reported adverse events were those related to the digestive system, body as a whole, skin and nervous system. The incidence and nature of adverse events observed for nimesulide-treated patients were similar to those of the placebo group. Nimesulide was particularly well tolerated by the liver, lungs, kidneys and blood.