COVID-19 patients can present gastrointestinal symptoms, being diarrhoea one of the most frequent, suggesting intestinal health can be impacted by COVID-19. Here, we will discuss whether there is a correlation between the presence of SARS-CoV-2 RNA in faeces and diarrhoea, the relevance of gastrointestinal symptoms in disease diagnosis and transmission, and how COVID-19 can impact the gut microbial balance. SARS-CoV-2 RNA has been reported in faeces or rectal swabs of COVID-19 patients with and without diarrhoea, suggesting faecal shedding can occur independently of gastrointestinal symptoms. However, the presence of the virus in the intestine can persist beyond its presence in the respiratory tract, with some reports suggesting that SARS-CoV-2 in the faeces can be infectious.COVID-19 can impact the gut microbiota causing an enhancement of biosynthesis pathways that favour the expansion of bacterial pathogens in the inflamed gut, and causing a decline in commensals involved in the human immune response. Gastrointestinal symptoms may be the first indication of COVID-19. SARS-CoV-2 in faeces can potentiate routes of disease transmission, particularly as the high viral loads reported in patients with severe illness suggest virus replication in the intestine may be possible.