Three-month-old babies wake up frequently at night to eat their hands, related to self-soothing, bad habits, improper feeding, teething, lack of calcium and other reasons. If the symptoms continue to be unrelieved, it is recommended to go to the hospital for examination in order to clarify the cause of the disease, according to the cause of the targeted treatment.1, self-soothing: due to the fact that adults seldom play with the baby, talk, the baby appeared to be lonely, the baby may be through the eating of the hand to self-soothing. Adults should accompany the baby more and interact with the baby more to relieve the symptoms; 2, bad habits: if the night frequently woke up to eat hands, it is a bad habit, may be related to imitation of adult action. You can prepare a soother for your baby, and the soother can satisfy your baby’s non-nutritive sucking and correct your baby’s bad habit of eating hands; 3. Improper feeding: If you feed your baby in an incorrect way, or if you feed too fast, you fail to satisfy your baby’s desire to suck. The baby’s stomach is full, but psychologically not yet satisfied, it will suck the hand instead. Usually let the baby have enough time to meet the requirements of sucking; 4, teething: baby in three months old, may grow teeth, teething will cause stimulation of the dental bed, the baby will appear itchy gums, which in turn triggered more saliva, like to bite things and other symptoms. Babies frequently wake up at night to eat their hands, may also be caused by itchy gums. You can prepare for the baby gum or teething stick, in the use of parents must be accompanied by the baby, so as to avoid accidents such as stuck choking; 5, lack of calcium: the baby lack of calcium will cause an increase in neural excitability, resulting in night terrors, leading to frequent waking up at night, and through eating hands to calm down. You can take calcium supplements, such as calcium gluconate, under the guidance of your doctor, and at the same time, you should get more sunshine to improve the symptoms.