A newborn’s tongue is white most commonly because a thin layer of milk remains after feeding, but persistent white patches may sometimes indicate oral thrush. This guide explains how to tell the difference by looking at the coating’s appearance, location, and whether it changes between feeds. It also covers feeding discomfort, breastfeeding-related thrush, diaper rash, safe mouth care, and cleaning feeding equipment. Parents will learn when simple observation is enough and when spreading patches, feeding difficulties, fewer wet diapers, fever, dehydration, or unusual sleepiness require advice from a pediatrician.