Effect of tranexamic acid on gross hematuria: A pilot randomized clinical trial study published in the American Journal of Emergency Medicine. The purpose of the study was to evaluate if local tranexamic acid will help control painless hematuria in the ED. This is a randomized double blind clinical trial study. 50 patients were evaluated with 25 being in the experimental group and 25 in the placebo group. 43 patients were male and 8 were female. Patients that were included in the study were 40 years or older and did not have a history of thrombosis, thromboembolism, coagulopathy, myocardial infarction or stroke, renal failure, and urinary tract infection. The patients were catheterized with a 3 way catheter. In the intervention group 500 mg of tranexamic acid was dissolved in 100 ml of normal saline for the irrigation and in the experimental group 100 ml of normal saline was used. In both groups the urinary flow was closed for 15 minutes to allow the drug to apply its effect. The patients were admitted and observed for 24 hours. The washing was constant until urine flow was transparent. The study concluded that the consumption of TXA reduced the washing serum volume significantly. However, there was no difference between hemoglobin and hematocrit levels between the two groups.  It was concluded that the use of tranexamic acid reduces the amount of washing serum to urine but it has not any effect on drop in hemoglobin or packed cell transfusions.