Objective To investigate the feasibility and clinical effect of tranexamic acid in prehospital emergency care of patients with craniocerebral trauma.Methods A randomized,placebo controlled trial was carried out on 77 craniocerebral trauma patients [Glasgow Coma Scale (GCS) ≤12 points]enrolled between May 2015 and December 2016.There were 45 males and 32 females,with an average age of 36.5 years (range,19-73 years).Among the patients,37 cases were caused by traffic accidents,19 falling from high places,11 falling when walking,and ten by being hit.According to the random number table method,they were divided into control group (39 cases) and treatment group (38 cases).The treatment group received 1 g of tranexamic acid by intravenous injection within ten minutes on the scene and another 1 g of tranexamic acid within eight hours at the hospital.The control group received 0.9％ isotonic saline.The operation and medication followed the routine process.The arrival time of ambulance and the time of first medication use were recorded.The plasma fibrin degradation products (FDP) and D-dimer at admission and 1 d post-trauma,the percentage of cranitomy operation,case fatality rate,red blood cell transfusion,length of stay in the neurosurgical intensive care unit (NICU),and the Glasgow Outcome Scale (GOS) at day 28 were all recorded and analyzed.Results No significant differences were found between the two groups in gender,age,injury causes,GCS,arrival time of ambulance,and the time of first medication use (P ＞ 0.05).The FDP and D-dimer at admission of the two groups were similar (P ＞ 0.05).One day after admission,the expression of plasma FDP was significantly lower in treatment group than that in control group [6758 (4732,13661) μg/L vs.11740 (8516,21756) μg/L] (P ＜ 0.01).The expression of D-dimer was significantly lower in treatment group than that in control group [1074 (849,1414) μg/L vs.1722 (1389,2330) μg/L] (P ＜ 0.01).Between group differences were insignificant in the percentage of craniotomy operation,case fatality rate,and red blood cell transfusion (P ＞ 0.05).However,treatment group showed shorter stay in NICU [4 (1,12)days vs.2 (0,4)days] and higher GOS [4 (3,5)points vs.5 (4,5)points]than control group (both P ＜ 0.01).Conclusions Tranexamic acid can be applied conveniently in pre-hospital emergency care of craniocerebral trauma patients.It can effectively realize the synchronization of pre hospital transport and treatment,eventually reducing the time of NICU treatment as well as improving the prognosis.