This study focuses on patients who are undergoing either an oral double balloon endoscopy procedure or an esophagogastroduodenoscopy procedure as part of their clinical care. The purpose of the study is to understand how microorganisms in the gut affect individuals and how they may contribute to gut-related human diseases. Researchers aim to examine gut microorganisms in the small intestine. Specifically, researchers would like to examine how various gut microbes may be affected by genetic makeup and affect which genes are turned on or off in various parts of the gut. The results will help researchers to better understand how gut microorganisms may contribute to gut-related diseases.