In this randomized, placebo-controlled trial conducted in 175 hospitals in 29 countries of adults with traumatic brain injury (TBI; n = 12,737) who were within 3 h of injury, had a Glasgow Coma Scale score of 12 or lower or any intracranial bleeding on CT scan, and no major extracranial bleeding, researchers evaluated the impacts of tranexamic acid in individuals with TBI. In individuals with a mild-to-moderate head injury, the risk of head injury-related death decreased with tranexamic acid although, in individuals with a critical head injury, it did not. In individuals with a mild and moderate head injury, early treatment was more efficient than was later treatment, however, in individuals with a critical head injury, time to treatment had no apparent impact. In the tranexamic acid and placebo groups, the risk of vascular occlusive events was comparable. The risk of seizures was also comparable among groups. Thus, these results exhibit that in patients with TBI, tranexamic acid is safe and that treatment within 3 h of injury decreases head injury-related death. Moreover, individuals should be treated as soon as possible following the injury.