My son went through the same thing and began refusing formula. Finally at 6 months my pediatrician recommended goats milk (he also said that it was typically shunned by the medical community but he has seen baby's thrive on it). My son is now 8 months and has been drinking goats milk for the past two months and is doing great. The only thing we had to add was an infant multivitamin because goats milk does not have the folic acid that they need. You can get it in a health food store in liquid form and then mix it with their food in the morning.