Hi, my son who is now 3 also had reflux, though not as severe as your grandson's seems to be. Zantac worked for my son; however, it doesn't work for everyone. There is alot more that can be done for him. Take him to a pediatrician, or call the GP you saw and ask him for a referral to a gastroenterologist (tummy doc) for your grandson. If you can get the GP to give a referral then you can save money since a pediatrician may just refer you to the tummy doc anyway. There are several other medications available that are more appropriate for reflux that a doctor can prescribe to your grandson. Also, if he is on formula still, you should try switching to a more gentle formula. Nutrimagen (made by similac) is a very good formula. It is usually recommended for babies with milk allergies but sometimes helps with reflux problems. My son does not have a milk allergy, but Nutrimagen was what we had to give him. Nutrimagen is already broken down and is very very easy to digest. I hope this advice helps, and I hope he feels better. (By the way, do not up the dosage of Zantac. It won't help. Zantac doesnt help with regurgitation, only with reducing the stomach acid which helps reduce pain and indigestion).