The preemptive use of anti-inflammatory drugs, such as corticosteroids and NSAIDs, has the potential to reduce pain, swelling and trismus following oral surgery. The aim of this study was to compare the efficacy of dexamethasone and ketorolac tromethamine in reducing pain, swelling and trismus after mandibular third molar removal. The researches implemented a triple-blind, randomized clinical trial. The study was conducted with ASA I individuals aging between 18 and 35 years, which were randomized and submitted to two interventions, one with 8mg dexamethasone and the other with 20mg ketorolac tromethamine given 1h before the procedure. The primary predictor variable was the use of dexamethasone or ketorolac. The primary outcome variable was the postoperative pain level, measured with a Visual Analogue Scale. The secondary outcome variables were the amount of rescue analgesic consumed, swelling and trismus. Repeated-measures ANOVA and t-test for paired samples were used to compare the means. Significance was set at p < 0.05. Fifty individuals were randomized and allocated to intervention, and the sample was composed of 40 subjects who completed the study (27 female and 13 male). Dexamethasone, when compared to ketorolac tromethamine, showed a significantly higher reduction in pain level at 8h, 16h, 24h, 32h, 40h and 72h, in swelling and trismus at 24h, 48h, 72h and 7 days and in total number of rescue analgesics taken up to 72h postoperative (p < 0.05). The clinical performance of dexamethasone in controlling pain, swelling and trismus after mandibular third molar removal was superior to ketorolac tromethamine?s.