One-month baby crying may be the external environment stimulation, or dietary factors, disease factors and so on. 1. external environmental stimuli: one month baby is still sensitive to changes in the external environment, such as the lights suddenly light up, the room is too cold or too hot, suddenly ringing noise, etc., the baby is easily stimulated, thus causing crying. 2. Dietary factors: for example, the baby will cry when hungry, after eating too much, may also cause indigestion, gastrointestinal dysfunction, abdominal pain, bloating, diarrhea and other symptoms, which will also cause the child to cry. 3. Disease factors: for example, the baby has enteritis, colds, eczema and other diseases, resulting in the baby’s body has symptoms of discomfort, thus causing the baby to cry. One-month baby crying, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.