###Human: Does changing the formula milk cause vomiting and diarrhea in a 4 weeks old baby? ###Assistant: Hello. From the reflux point of view, the first thing that is to be done is to keep the baby at an angle of 35 degrees to the ground level after feeding. This will reduce the chances of reflux more than any medication. The next thing to be done before feed thickening is to start the child on Perinorm (Metoclopramide) and Rantac (Ranitidine). If all these do not work, food thickening is to be done. Also, I would recommend you to get a reflux study of the child done for a better knowledge of what grade of reflux the child is suffering from.