Diarrhoea is liquefied faeces, which is released frequently and in large quantities for a period of time. It is a reaction of the body to quickly excrete the intestinal contents. It can have numerous specific causes, including incorrect feeding, constant acidity, lack of raw fibre, grazing too quickly, internal diseases, infections or worm infestation. Diarrhoea can be mild or life-threatening in horses. It is advisable to have the cause clarified by a veterinarian.