This study involves a medical device in the form of syrup, not yet on the market and tested for the first time in humans, named "FIBROIN SYRUP". The intended use is to reduce the GastroEsophageal Reflux Disease (GERD) symptoms such as heartburn, epigastric pain, irritative and nocturnal cough, dysphagia and dysphonia, which may occur especially after meals or during the night due to lying position. "FIBROIN SYRUP" has never been tested on humans and this study aims to evaluate the safety, tolerability and efficacy of the medical device when taken after the main meals (breakfast, lunch, and dinner; total: 3 sticks/day) for 6 weeks.