The lack of energy and drowsiness after diarrhea in babies usually recovers after 3-7 days when the diarrhea improves, but the exact time should depend on the severity of the child’s condition. The lack of energy and lethargy after diarrhea is caused by pathogenic bacterial infections that cause diarrhea, and the toxins of the pathogenic bacteria circulate throughout the body, thus affecting the mental state. In this case, the baby can return to normal after timely consultation and removal of the cause of diarrhea. On the other hand, it is caused by severe dehydration after diarrhea. With the discharge of stool, more water and electrolytes are excreted together with the diarrhea, resulting in dehydration and electrolyte disorders, which cause lack of energy and drowsiness. After rehydration, the water and electrolytes are balanced and the baby returns to normal. Usually, children with diarrhea can recover in 3-7 days, but the exact time required depends on the baby’s own constitution and the severity of the disease, and the more severe the dehydration, the longer the recovery time. In addition, during diarrhea, babies should eat a light diet, reduce the amount of meals and eat more often, but not too often, in order to reduce the burden on the baby’s stomach and intestines.