Hi, my daughter also used to do this when she was a child, although not as often. It always seemed like the vomit was full of mucus (not to gross you out!). So mucus irritating the stomach is certainly a possibility. I also think that the teething could be a problem, and acid reflux irritating the esophagus could cause you to gag. But also consider food allergies. When my daughter got older, we found out that she has several food allergies, and I wonder if that’s what caused her to vomit when she was younger.