Objective:The aim of the present study was to evaluate the synergistic anti-inflammatory effect of Non-steroidal anti-inflammatory drugs (NSAIDs) plus B vitamins administered pre and postoperatively in surgeries of impacted mandibular third molars. Material and Methods: Double-blind randomized clinical trial, sixty-six patients participated and were randomized into 2 groups. The control group was administered meloxicam 15 mg intramuscularly plus placebo orally and to the experimental group, meloxicam 15 mg intramuscularly plus vitamins B [B1, B6, and B12] orally; both treatments were administered preoperatively. The anti-inflammatory effect was evaluated by pain intensity, facial swelling (facial contour measurements), and mouth opening (distance between the upper and lower incisors) during the post-surgical phase. Student's t-test was performed for independent samples. Results: In all the evaluated times (1 hour, 6 hours, 12 hours, 24 hours, 2 days, and 3 days after the end of the surgery) the experimental group presented a significantly lower intensity of pain compared to the control group (p<0.05). The highest pain intensity was recorded at 6 hours (17.7 ± 9.1 mm in the experimental group and 34.5 ± 21.3 mm in the control group). Swelling and mouth opening were similar in both groups, at all times evaluated (p>0.05). Conclusion: In the present study, the administration of NSAIDs plus B vitamins (B1, B6, B12) produced lower intensity of pain compared to the administration of only NSAIDs. Nevertheless, swelling and mouth opening were similar in all evaluations for both study groups.