Cow's milk causing diaper rash and diarrhea? — The Bump
I found that it was the milk causing my little guys rashes. I went from 20-24 ounces of milk to 16 ounces or less a day and usually do half milk half water. His rash has cleared up. I think his body just can't handle the new protein in the milk so introduce it slowly and back off the milk until his rash goes away, then slowly reintroduce it.