Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 14 1 2022 02 19 1 9 Nazanin Alibeik Department of Internal Medicine, School of Medicine, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran Elham Pishgar Gastrointestinal and Liver Diseases Research Center, Iran University of Medical Sciences, Tehran, Iran Ramin Bozorgmehr Department of Surgery, School of Medicine, Shahid Madani Hospital, Alborz University of Medical Sciences, Karaj, Iran Farshad Aghaaliakbari Department of Internal Medicine, School of Medicine, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran Neda Rahimian Department of Internal Medicine, School of Medicine, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran; Endocrine Research Center, Institute of Endocrinology and Metabolism, Iran University of Medical Sciences (IUMS), Tehran, Iran 2021 02 22 2021 05 29 Coronavirus Disease 2019 (COVID-19) is a pandemic disease caused by a new corona virus. COVID-19 affects different people in different ways. COVID-19 could affect the gastrointestinal system via gut microbiota impairment. Gut microbiota could affect lung health through a relationship between gut and lung microbiota, which is named gut-lung axis. Gut microbiota impairment plays a role in pathogenesis of various pulmonary disease states, so GI diseases were found to be associated with respiratory diseases. Moreover, most infected people will develop mild to moderate gastrointestinal (GI) symptoms such as diarrhea, vomiting, and stomachache, which is caused by impairment in gut microbiota. Therefore, the current study aimed to review potential role of gut microbiota in patients with COVID-19, its relation with lung axis, Central Nervous System (CNS) axis and improvement with probiotic therapy. Also, this review can be a guide for potential role of gut microbiota in patients with COVID-19. https://ijm.tums.ac.ir/index.php/ijm/article/view/3001 https://ijm.tums.ac.ir/index.php/ijm/article/download/3001/1418