Vomiting After Starting Whole Milk

My daughter is 10-months old and I am trying to wean her from breast milk to whole milk.  I normally breast feed her four times a day.  I tried introducing a small amount of cow's milk today after a short breast-feeding.  She took all of the milk with no problem, but a couple hours later she vomited it all up.  What should I do?  Does this mean she may have a milk allergy?  Should I try introducing cow's milk again or wait until closer to 12 months?

I doubt this is a serious issue since it has only happened once. While this could be a recurrent medical issue, her vomiting is unlikely to return with a second attempt.

This does not sound like a lactose intolerance problem as both cow’s and breast milk contain lactose. She could have a cow’s milk protein intolerance. The protein found in cow’s milk is different than those of breast milk and formula. In some children, these proteins can cause stomachaches, diarrhea and even vomiting.

Does she regularly drink from a bottle or sippy cup? If she is new at sippy cups or bottles she may have ingested excess milk or air while swallowing. Was the cow’s milk served cold? Has she tolerated other cold beverages? Swallowed air, excess milk, or cold temperature could lead to vomiting.

If you haven't already, retry the cow’s milk. Serve her cow’s milk in a bottle or sippy cup familiar to her. Try a small amount 2-4 ounces along with a meal. If her vomiting returns discuss this with her doctor.

Follow up

Thank you so much for your reply. I have stopped nursing because I'm expecting our second child. She did vomit two other times after offering her milk (this was before receiving your e-mail). Both times she drank a couple ounces in a bottle. Now, I am offering her milk in a sippy cup with her meals, she hasn't vomited anymore, but she is only drinking a tiny bit of milk (maybe an ounce a day). She doesn't seem to like it very much, but I will continue to offer it to her and hopefully she will acquire a taste for it. Thank you so much for your time! Your website has been so helpful to me!

Written January 2011 by
Dr. Gordon, Orlando Pediatrician