Purpose The objective was to collect the data available regarding the presence of laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in gastrointestinal system and to evaluate whether the digestive system could contribute to viral transmission. Methods Bibliographic databases were searched to identify all studies documenting, in adult patients with a confirmed diagnosis of coronavirus disease 2019 (COVID-19): (1) the presence of SARS-CoV-2 ribonucleic acid in the feces; (2) the presence of SARS-CoV-2 ribonucleic acid in the intestinal cells; (3) live SARS-CoV-2 in the feces. Results Twenty seven met the inclusion criteria. In 26 studies, the presence or absence of SARS-CoV-2 ribonucleic acid in the feces of COVID-19 patients had been reported. Out of the 671 patients, 312 (46.5%) had a positive stool sample for viral nucleic acid. Of these patients, 63.9% remained positive for viral nucleic acid in the feces after pharyngeal swabs became negative; Three studies also evaluated the viral ribonucleic acid in the gastrointestinal tissues and the presence of SARS-CoV-2 nucleic acid was found in samples of 3 patients out of 8 examined (37.5%). The presence of the live virus in stool samples was confirmed in two studies but no in in a recent study from Germany. These results suggested that SARS-CoV-2 could infect gastrointestinal epithelial cells and it may be transmitted through the digestive tract. Conclusion In order to control the pandemic, every effort should be made to understand all the possible routes of transmission of the infections, even the less important ones. Keywords COVID-19. Feces. Fecal-oral transmission. Gastrointestinal system. Severe acute respiratory syndrome coronavirus 2 "Sed domus corporibus exanimis, itinera funeribus complebantur; non sexus, non aetas periculo vacua; servitia perinde et ingenua plebes raptim extingui, inter coniugum et liberorum lamenta, qui dum adsident, dum deflent, saepe eodem rogo cremabantur." Annales XVI, 13 Tacito "Yet the houses were filled with lifeless bodies, the streets with funerals. Neither sex nor age gave immunity from danger; slaves and the free-born populace alike were summarily cut down, amid the laments of their wives and children, who, themselves infected while tending or mourning the victims, were often burnt upon the same pyre." Annals Book XVI, 13 Tacitus * Dajana Cuicchi