 SARS-CoV-2 infection manifests mainly by involving the respiratory system. Due to the presence of abdominal symptoms, the digestive system is clearly involved in the expression, transmission, and possible pathogenesis of COVID-19. There are many theories regarding the development of abdominal symptoms, including angiotensin-2 receptor, cytokine storm, and disturbances of the intestinal microbiome. This paper provides an overview of the most important meta-analyses and publications on gastrointestinal symptoms and the gut microbiome in COVID-19. This article was authored by Konrad Lewandowski, Magdalena Kenuska, Mariusz Rosalowski, and others.