Coronaviruses cause several human diseases, including severe acute respiratory syndrome. The global coronavirus disease 2019 (COVID-19) pandemic has become a huge threat to humans. Intensive research on the pathogenic mechanisms used by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is urgently needed-notably to identify potential drug targets. Clinical studies of patients with COVID-19 have shown that gastrointestinal disorders appear to precede or follow the respiratory symptoms. Here, we review gastrointestinal disorders in patients with COVID-19, suggest hypothetical mechanisms leading to gut symptoms, and discuss the potential consequences of gastrointestinal disorders on the outcome of the disease. Lastly, we discuss the role of the gut microbiota during respiratory viral infections and suggest that targeting gut dysbiosis may help to control the pathogenesis of COVID-19. Coronaviruses are enveloped RNA viruses containing a large (25 to 32 kb), single-stranded, positive-sense RNA genome. These viruses circulate continuously in human populations and generally cause mild respiratory diseases, including the common cold. In contrast, the zoonotic severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) cause severe respiratory diseases and are associated with a high mortality rate when they spread to humans (Fehr et al., 2017). No specific antiviral drugs or vaccines have been approved for combating infections by SARS and MERS. In late 2019, a new infectious respiratory disease (now termed coronavirus disease 2019 [COVID-19]) emerged in Wuhan, China (Wang et al., 2020a; Zhu et al., 2020). This disease spread rapidly across China and to other countries. The World Health Organization recently declared the COVID-19 outbreak to be a pandemic. SARS-CoV-2 is the etiological agent of COVID-19 (Zhu et al., 2020). A phylogenetic analysis has shown that SARS-CoV-2 is most closely related to SARS-CoV (nucleotide similarity: 89.1%). COVID-19 is characterized by acute pathological outcomes, including pneumonia and acute respiratory distress syndrome (ARDS), and has a substantial mortality rate (Chen et al., 2020). ARDS during a SARS-CoV-2 infection is also associated with dysregulation of cytokine production, barrier leakage, and organ dysfunction. COVID-19 is more severe in individuals with comorbidities (diabetes mellitus, cardiovascular diseases, and hypertension) and in the elderly (Guan et al., 2020; Wu and McGoogan, 2020).