Diarrhoea is defined as loose, liquid, or watery stools more than 3 times per day. It is mainly caused by viral, bacterial, and parasitic infections transmitted through the fecal-oral route. The major causes of diarrhoea globally are rotavirus infection in children under 5 years old and enterotoxigenic E. coli (ETEC) infection, which is the most common cause of traveller's diarrhea. Host factors like malnutrition and environmental factors like lack of access to clean water and sanitation also contribute significantly to the high global burden of diarrhoeal diseases.