Sour stools are mostly caused by digestive disorders such as chronic pancreatitis, chronic active hepatitis, intestinal mucosal enzyme deficiency and other intraluminal digestive disorders, as well as intestinal mucosal absorption disorders such as meconium enteropathy and tropical stomatitis diarrhoea, which can result in poor digestion or absorption of fats and sugars, leading to sour stools. In addition, poor dietary habits, such as consuming too much fatty food at once, can also lead to sour stools.