A three-month-old baby tearing and crying may be caused by hunger and bowel movements, but if it is more violent than usual, it is considered that there is discomfort and needs to be sent to the hospital immediately for examination to clarify the cause. A physiological phenomenon: such as baby hunger, thirst for comfort or wet diapers after urination and defecation discomfort, etc., will appear more than crying phenomenon. Parents need to pay attention to observe and judge the baby’s needs after feeding, putting to sleep, changing diapers, etc. Second, the pathological phenomenon: 1, intestinal obstruction, intussusception: the occurrence of intestinal obstruction, intussusception of the child, the abdomen will have severe pain and discomfort, the baby by tearing the way to cry to alert parents, at this time the baby can not stop crying through comfort, it is recommended that immediately sent to the hospital, through palpation, colonoscopy to clarify the diagnosis. If suffering from intestinal obstruction, intussusception, can be treated through ultrasound under the water pressure enema reset way; 2, lack of vitamin D or calcium: if the baby body lack of vitamin D or calcium elements, there will be sleep instability, easy to wake up, head sweating, loud crying symptoms. Need to go to the hospital to check the content of trace elements in the body, through the daily diet or oral vitamin D preparations, calcium tablets, etc. to supplement the lack of trace elements in the body; 3, other: intestinal perforation, acute cholecystitis, acute appendicitis and other diseases can appear such cases, should promptly seek medical attention to clarify the cause after treatment.