OK. So far so good. I switched Tuck to Carnation Good Start and Neocate mixed yesterday. He has not gotten sick SO FAR. We are not going to hold our breathe and call it good yet. He started a little cold or sinus stuff this weekend also so he has been coughing and kinda acting as if he could get sick. We are not sure if that is the sinus-congestion doing it or if it is the milk based formula. SOOOOO, we are going to stay on 1/2 and 1/2 for this week and possibly go up to 3/4 and 1/4 next Sunday-IF we stay good with no signs of allergic reaction. Cross your fingers.