Can breast milk and formula be mixed?

In general, having a combination of both breastfeeding and formula will not cause any direct harm to the baby. As long as you are breastfeeding, the baby will be able to get the antibodies produced by the mother’s body to help protect them against infections. That being said, if you baby is below six months of age, consuming anything other than breast milk may expose his/her immature immune system and gastrointestinal tract to inflammation and disease. Also, there is a chance that your supply may be affected because the production of breast milk is related to the frequency and amount of breastfeed (especially if your baby is a newborn). Here’s an article that touches on mix/combination feeding: http://www.wewomen.com/baby-first-year/everything-you-need-to-know-about-combination-or-mix-feeding-your-baby-s429192.html