Undigested food in the bowel movement is generally abnormal, and is usually a sign of gastrointestinal dysfunction. If the patient is an infant, the baby’s gastrointestinal function is relatively poor, if the baby is not fed properly, the baby can’t digest and absorb the food thoroughly, and the manifestation of undigested food in the bowel movement can occur. If the patient is an adult, the presence of undigested food in the stool suggests that the patient’s gastrointestinal function is reduced, and the food can not be fully digested, absorbed and utilized, which is mostly seen in gastric motility insufficiency, gastritis, enteritis, and overfeeding. In addition to the above reasons, there are many other diseases that may lead to undigested food in the patient’s bowel movement, and the patient should consult a doctor to clarify the cause of the disease and get timely treatment to avoid delaying the condition.