GERD is one of the most prevalent pathologies in the digestive tract. Barrett's esophagus, a complication of chronic GERD, has attracted the attention of researchers due to its condition of pre-neoplastic lesion. At present, treatment of Barrett's patients is limited to acid inhibition with PPIs. Although there are several studies which indicate that treatment with PPIs could decrease the incidence of high grade dysplasia and EAC, treatment with PPIs does not eliminate the risk of EAC in these patients. Therefore, it is necessary to find chemo-preventive agents that stop neoplastic progression of Barrett's esophagus. Among them, antioxidants have become the most promising agent. This pilot study will determine the efficacy of melatonin in the chemoprevention of EAC.