Thrush is a yeast infection commonly seen in a baby's mouth. Thrush appears as whitish-gray elevated patches that look like cottage cheese or milk curds. They are found on the insides of a baby's cheeks, tongue and gums. These patches will not wipe off and may become red and raw if you try to wipe them off.

If there are many of these patches, your baby may have pain while sucking and will not drink as well.