Why is my baby's tongue yellow?

In the first days after birth, breastfed babies drink colostrum. HealthyChildren.org, the American Academy of Pediatrics parent site, describes it as a thick, somewhat sticky milk that is usually yellow or orange. It is produced for several days until mature milk comes in. A little colostrum or milk left on the tongue can easily look yellow.

Later on, milk or formula residue can still look cream to yellow, depending on the feed and the light. The AAP symptom checker notes that a white tongue alone is often caused by a milk diet and is not thrush. The same reasoning applies to a pale yellow film that sits only on the top of the tongue and wipes away.

For the white version of this, see our guide to milk tongue vs thrush.

The NHS describes thrush in babies as a white coating on the tongue that may turn yellow or gray and look like cottage cheese, sometimes with white spots elsewhere in the mouth. HealthyChildren.org also describes white or yellow patches on the tongue, lips, gums, palate and inner cheeks. A baby with thrush may not want to feed, and thrush can come with a yeast diaper rash.

Thrush is common and treatable, but it needs a professional to confirm it. The NHS advises seeing a doctor if a baby under 4 months has signs of thrush, because pharmacy gels are only suitable from 4 months.

Jaundice comes from a build-up of bilirubin and is common in newborns, usually most noticeable around day 3. The NHS lists yellow under the tongue or inside the cheeks as a sign, along with yellow whites of the eyes and yellow skin that usually starts on the face. On brown or black skin, the mouth and eyes may be the easiest places to see it.

To check, look under your baby's tongue and inside the cheeks in good daylight, and look at the whites of the eyes. A coating sits on top and wipes off; jaundice is in the tissue and does not.

• If your baby is under 24 hours old and looks yellow, the NHS says to call emergency services or go to the emergency department.
• If your baby is older than 24 hours, contact your pediatrician or midwife the same day.
• The AAP advises calling the doctor if jaundice persists beyond 2 weeks in formula-fed babies or 4 weeks in breastfed babies.
• Dark yellow or brown urine, or pale, creamy stools, need prompt medical review.

1. Wash your hands and wrap a clean finger in damp gauze or a soft washcloth.
2. Gently wipe the tongue. The AAP recommends wiping your baby's gums with a clean damp cloth or gauze after feeds, and this is the same motion.
3. If the yellow film comes off easily and your baby is feeding well, it was almost certainly milk.
4. If it does not come off, or the yellow is under the tongue rather than on top, check the eyes and skin and call your pediatrician.

Never use a tongue scraper, toothbrush bristles, cotton swabs pushed into the mouth or any adult oral product on a baby's tongue. For safe tools by age, see how to clean your baby's tongue.

Whatever the tongue looks like, these signs matter more. The NHS and AAP advise urgent care for a baby who is very sleepy or hard to wake, not feeding, floppy or stiff, has a temperature of 100.4°F (38°C) or higher, or is breathing with difficulty. Fewer wet diapers than usual, dark urine, a dry mouth, a sunken soft spot or no tears can mean dehydration, which needs prompt attention in a young baby.