Diarrhoea is defined as the passage of three or more loose or watery stools per day, often resulting from infections, malabsorption, or inflammatory conditions. It is clinically significant due to its potential to cause dehydration, electrolyte imbalances, and nutritional deficiencies, particularly in vulnerable populations such as children and the elderly. A key association is acute gastroenteritis, which can lead to severe complications if not managed promptly.