Jean:
Is he on regular milk now? If not it could more likely been the milk that caused his gas and pain or just the overall sugar overload.
Hard to say. I am sure other things you give him have sugar in them though, snacks, etc.
I researched gas and sucrose (carbohydrate malabsorption) when I was trying to figure out what was causing Tyler's problem. Granted since we have found out he cannot have potato's either, his gas has stopped 100% (unless he eats dairy), BUT before that he was SO gassy with Alimentum Ready to feed and barely any with Nutramigen.
If you google it, you can read a lot of info.
It just made perfect since to me and explained why he was so gassy with that formula. BUT, so many other's have had great success with it.