Health Library
Warming Formula or Breast Milk

How Do You Warm Formula or Breast Milk?

Although room temperature formula or breast milk is fine for your baby, some babies prefer to have breast milk warmed.

If that is your baby's preference, warm his or her bottle safely by following the instructions below.

Warming Formula or Breast Milk

  1. Warm the bottle in warm − not boiling − water by one of these two methods:
    • Put the bottle in a container of warm water for a few minutes.
    • Run warm tap water over the bottle for a few minutes.

Don't let the water reach the lid of the bottle (to avoid contamination).

  1. After warming the bottle, gently swirl to mix fat and nutrients.
  2. Test the temperature of the liquid before feeding it to the baby by putting a few drops of breast milk or formula on the inside of your wrist. It should feel comfortably warm.


Do not use a microwave to warm formula or breast milk. You should never use a microwave to heat a baby's bottle because:

  • Microwaves cause "hot spots" when used to warm breast milk. There is a very serious risk of burning your baby's mouth, throat and esophagus (the tube that goes to your baby's stomach). This can happen even if you shake the bottle after you warm it in a microwave.
  • Breast milk, if heated too much, can lose some of its benefits for your baby.
  • A bottle that has been warmed in a microwave can cause a burn from hot liquid or steam.

Use caution when using bottle warmers. It can be difficult to get just the right level of heat.

Contact Us

For additional information on this Health Topic, call the Center for Breastfeeding Medicine at 513-636-2326, or call your pediatrician.

Last Updated 06/2021

Reviewed By Roma Seat, Lactation Consultant