If your baby has symptoms of persistent vomiting that does not heal, you should go to the hospital for some tests. For this kind of symptoms more commonly used tests are: 1, chest and abdomen not standing prone film 2, upper gastrointestinal tract imaging: its the most useful diagnostic method to check the function of the esophagus, easy to do. It is possible to observe the passage of the contrast agent through the esophagus, the presence of reflux from the stomach to the esophagus, as well as the presence of inflammation, narrowing of the esophagus, the normal position of the stomach, and the presence of lesions in the duodenum, etc. It is possible to identify various lesions in the upper gastrointestinal tract, such as cardia achalasia, gastroesophageal reflux, gastric torsion, congenital pyloric stenosis, duodenal obstruction, etc. 3, B-type ultrasound examination: its non-invasive to small babies, convenient examination, more practical. It can determine whether there is gastroesophageal reflux by observing whether there is filling at the lower end of the esophagus and whether there is liquid flowing back and forth between the stomach and the esophagus. 4.Esophageal pH measurement: its need for certain conditions, if 24 hours continuous monitoring, it can significantly improve the positive rate, so the operation is slightly troublesome, but the sensitivity is high. 5.Esophageal pressure determination: It is a new technique of examination carried out in recent years, mainly to determine the pressure at the lower end of the esophagus and analyze the function of the lower esophageal muscles. It also requires certain equipment and is slightly less sensitive. Of course, these tests should be selected according to the specific condition