A tremendous amount of data from research was published over the past decades concerning the roles of different vitamins in various gastrointestinal diseases.For instance,most vitamins showed an inverse relationship with the risk of colorectal carcinoma as well as other malignancies like gastric and esophageal cancer in observational trials,however interventional trials failed to prove a clear beneficial preventive role.On the other hand,more solid evidence was obtained from high quality studies for a role of certain vitamins in specific entities.Examples for this include the therapeutic role of vitamin E in patients with nonalcoholic steatohepatitis,the additive role of vitamins B12 and D to the standard therapy of chronic hepatitis C virus,the role of vitamin C in reducing the risk of gallstones,the positive outcome with vitamin B12 in patients with aphthous stomatitis,and the beneficial effect of vitamin D and B1 in patients with inflammatory bowel disease.Other potential uses are yet to be elaborated,like those on celiac disease,pancreatic cancer,pancreatitis,cholestasis and other potential fields.Data from several ongoing interventional trials are expected to add to the current knowledge over the coming few years.Given that vitamin supplementation is psychologically accepted by patients as a natural compound with relative safety and low cost,their use should be encouraged in the fields where positive data are available. A tremendous amount of data from research was published over the past years concerning the roles of different vitamins in various gastrointestinal diseases. For instance, most vitamins showed an inverse relationship with the risk of colorectal carcinoma as well as other malignancies like gastric and esophageal cancer in observational trials, however interventional trials failed to prove a clear beneficial preventive role.On the other hand, more solid evidence was obtained from high quality studies for a role of certain vitamins in specific entities. Examples for this include the therapeutic role of vitamin E in patients with nonalcoholic steatohepatitis, the additive role of vitamins B12 and D to the standard therapy of chronic hepatitis C virus, the role of vitamin C in reducing the risk of gallstone, the positive outcome with vitamin B12 in patients with aphthous stomatitis, and the beneficial role of vitamin C in reducing the risk of gallstone effect of vitamin D and B1 in patients with inflammatory bowel disease. Other potential uses are y et to be elaborated, like those on celiac disease, pancreatic cancer, pancreatitis, cholestasis and other potential fields. Data from several ongoing interventional trials are expected to add to the current knowledge over the coming few years. Given that vitamin supplementation is psychologically accepted by patients as a natural compound with relative safety and low cost, their use should be encouraged in the fields where positive data are available.