<s>[INST] my 10 month old son has been projectile vomiting most nights for 4 weeks we have had him at the hospital but they said it was just a tummy bug, he is well in every other way but at night he wont sleep more than 2 hours befor being sick again, what can be causing this? [/INST] HiWelcome to the HCM The most likely reason for vomiting spells only at night may be gastroesophageal reflux disease ( GERD) or gastritis. To confirm the diagnosis pH studies are available in hospitals. Measures such as keeping child upright for a while after feeds, pro kinetic agents like Syp. Perinorm and head end elevation at sleep are useful measure to avoid GERD. You may also give him antacids such as Syp. Digene for relief from gastritis.Hopefully this will be useful.Take care </s>