Babies waking up suddenly and crying at night may be caused by hunger, abdominal discomfort, vitamin deficiency, etc. It is recommended to breastfeed or consult a doctor promptly. 1. Hunger: Babies who feel hungry may not be able to sleep and cry more than once, they should be soothed and breastfed in time. 2. Abdominal discomfort: abdominal pain, diarrhea, constipation, abdominal distension, intestinal obstruction, etc. can cause abdominal discomfort in babies. If the attack occurs at night during sleep, there may be a sudden awakening during sleep and crying, it is recommended to seek medical treatment in time to find out the cause of the disease, do not take drugs casually. 3. Nutritional deficiencies: lack of vitamin D or calcium deficiency, increased nerve excitability, may also cause similar symptoms, should be supplemented according to the situation to the baby vitamin D or calcium, more sunshine, more exercise. In short, the baby appeared abnormal, it is recommended to consult a doctor in time.