Four-month-old baby dry cough and vomiting, related to improper feeding, or bronchitis, gastroesophageal reflux and other diseases. 1. Improper feeding: If the posture is not correct during the feeding process, resulting in the baby swallowing a lot of air, may cause irritating cough, coughing and vomiting occurs when the cough is intense. 2. Bronchitis: mainly associated with infection with bacteria, viruses, mycoplasma, when the pathogenic bacteria repeatedly stimulate the bronchial mucosa prone to irritating cough, coughing is more intense when there will be regurgitation, nausea performance. 3. Gastroesophageal reflux: when the solution in the stomach refluxed into the esophagus, easy to cause nausea, vomiting, dry heaving and other symptoms, severe irritating cough, and will often acid reflux, affecting appetite. Four-month-old baby dry cough and nausea, there may be other reasons, 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.