Dry heaving in three-month-old babies may be caused by physiological factors, or it may be caused by gastroesophageal reflux, upper respiratory tract infection, indigestion and so on. 1. Physiological factors: If a three-month-old baby is not fed properly, is overfed or inhales a lot of air during breastfeeding, it may cause dry heaving, or even the symptom of overflow of milk. 2. Pathologic factors: (1) Gastroesophageal reflux: because the gastrointestinal tract of three-month-old infants is not yet structurally well developed and is in a horizontal position, it is easy to reflux, and when the stomach contents are small and irritate the pharynx, the manifestation of dry retching may occur. (2) Upper respiratory tract infection: three-month-old babies’ immunity is low, easy to be invaded by viruses and bacteria, resulting in upper respiratory tract infections, fever, headache, nasal congestion, runny nose and other symptoms, but also loss of appetite, dry heaving and other manifestations. (3) indigestion: three-month-old infants who are not fed properly, overfeeding or inhaling a lot of air during breastfeeding can cause gastrointestinal dysfunction, nausea, vomiting, bloating, regurgitation and other symptoms. Three-month-old babies dry heaving may also have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.