The sour odor of the baby’s stool is considered to be caused by indigestion, fructose intolerance, wheat gum enteropathy and other factors. 1. Indigestion: improper artificial feeding, improper addition of complementary foods, Helicobacter pylori infection can lead to indigestion, resulting in crying, nausea, vomiting and other symptoms, and the stool can have a sour odor. 2. Fructose intolerance: it is an autosomal recessive disease, caused by gene mutations in fructose metabolism disorders, usually the younger the age of onset, the more severe the symptoms, usually in the first consumption of food containing fructose onset, the child will appear nausea, fatigue, sweating and other hypoglycemic symptoms, which can be accompanied by hepatomegaly, jaundice and other phenomena, and the stool has a sour smell. 3. Wheat glue enteropathy: also known as celiac disease, the child will be triggered after consuming food containing gluten wheat glue protein, the child will have abdominal distension, fecal abnormality (i.e., the stool is dilute and watery or large, pale, foamy, and accompanied by a sour smell), vomiting, weight loss and other phenomena. It is recommended that the child be seen by a pediatrician in a timely manner to identify the cause of the disease and follow the doctor’s instructions for standardized treatment.