<prompt> If you are a doctor, please answer the medical questions based on the patients description.My son is 11weeks old and we started him on enfamil newborn and he was really gassy and in discomfort, even with the gas relief drops he was still in discomfort. So then I switched him to the enfamil gentlease and it was even worse and would have screaming episodes, and he would only eat 2-3oz per feeding and refused to eat anymore. After 3 weeks I switched him to the enfamil prosobee and that has made him constipated and still in the discomfort from gas.. Any advice on which formula would be best for him? Thank you, Kristin  <response>: Thanks for follow up. I really surprised that you started from soybeans formula. He can not tolerate dairy? If he doesnt have problems and lactose insufficiency You can change gradually to NAN 1, start from 30 ml, then add every day more, for example: 1 day 1 feeding30 ml NAN 60-70ml Enfamil2 day 1 feeding60 ml NAN30-40 Enfamil3 day 1 feeding90-100 ml NAN, other feedings-Enfamil4 day 2 feedings NAN, other Enfamil5 day 3 feedings NAN etc. Continue to give gas relief Chat Doctor. 