Introduction: Traumatic brain injury is the leading cause of death and disability in young adults. Green tea Epigallocatechin-3-gallate (EGCG) supplementation favorably influenced many of the processes mention in the secondary insult of brain injury, including neuroinflammation and anti-oxidative damages in animal studies. In current study, we aimed to investigate the effect of EGCG on outcomes of traumatic brain injury. Materials and Methods: In a clinical trial, 30 patients with head trauma hospitalized in the intensive care unit of Sina hospital, Tehran, Iran were randomly divided into two groups. These groups included 15 patients who received a single daily oral dose of EGCG (400 mg) for 7 days and control group of 15 patients received placebo (distilled water) for the same period. Protein level S100 B and GCS were investigated between the two groups. Results: EGCG increased Glasgow coma score scale. However EGCG had no significant effect on the level of protein S100B. Conclusion: EGCG may play a neuroprotective effect in trumatic brain insulats.