You expect things to change day-by-day when you have a toddler, but the color of his tongue normally isn't one of them. It's a little disconcerting to notice that your toddler's wide-mouthed grin now features a gray tongue. In many cases, a change in his tongue color is the harmless result of something he ate, a medication or a common infection. Rarely, a gray tongue could indicate a more serious health problem, such as anemia. Have your toddler's pediatrician take a look at him if a little detective work doesn't turn up an obvious cause.
If you gave your toddler a chewable bismuth subsalicylate for a stomachache, or if he found one lying on the bathroom counter and decided to sample it, you've likely found the culprit for your toddler's gray tongue. While doctors recommend caution when giving this common over-the-counter medication to children, because it contains salicylate, the same ingredient found in aspirin, it's a common medication found in many homes. A gray or black tongue is the startling but temporary and harmless side effect of taking this medication.
A fungal infection can cause your toddler's tongue to develop white or gray patches. A yeast infection, commonly known as thrush, might look like milk or cottage cheese stuck to your toddler's tongue, lips of sides of his mouth, but if you try to pick the discolored areas off, you find they're stuck on and bleed. Your doctor can prescribe medication to clear up thrush, but if your toddler uses a pacifier, discard it and buy a new one and wash any toys or anything else that goes in his mouth thoroughly. If you're still breastfeeding, check your nipples to make sure you aren't harboring the infection, too. Scarlet fever -- a strep infection with a rash -- can also cause a white coating on the tongue.
Anemia -- a low hemoglobin level -- can cause your toddler's tongue, as well as the rest of his skin, to look pale or gray. This happens because the red blood cells that carry hemoglobin shrink in size or number. Toddlers have a high risk for anemia because many turn into picky eaters almost overnight. At the same time, many stop drinking iron-fortified formula and replace it with milk, which is low in iron. Your child's pediatrician can check for anemia with a simple blood test.
There's a saying in medicine that says, "When you hear hoofbeats, think of horses, not zebras." In other words, look for a common cause before searching for some unusual cause when your toddler sticks out his gray tongue. Sucking on black licorice or other dark-colored candy could give your toddler a temporarily ghoulish-looking dark tongue.