ObjectiveEvaluate the efficacy of tranexamic acid in reducing bleeding in patients undergoing total knee arthroplasty.Methods101 patients were randomized into two groups: the tranexamic acid group (n = 51) and the placebo group (n = 50). Patients were compared regarding the following parameters: reduction of hemoglobin, total estimated blood loss, drain output, and postoperative blood transfusion rate.ResultsComparing the groups, there were statistically significant differences (p < 0.05) in the following parameters: reduction of hemoglobin, decreased hematocrit, estimated blood loss, and drain output. All values were lower in the tranexamic acid group. Only placebo group patients required blood transfusion.ConclusionThe use of intravenous tranexamic acid is effective to reduce bleeding in patients undergoing total knee arthroplasty.