My child used to wake up some times on the mid night, coughing and then vomiting, what can cause this? he is 2 yrs old and this came since one yr.

Coughing: He may have an allergic nose or esophageal reflux. See your pediatrician for turther help.

Gastroesophageal ref: Gerd or eosinophilic esophagitis. You need to have him treated to prevent damage to the esophagus or aspiration complications.

Several conditions : Several conditions may cause these symptoms. Occurrence at night is associated with reflux,asthma and post nasal drip. Use nasal saline and gently suction prior to bedtime.