When must i speak to a dentist about my yellow tongue?

Thrush: If there is pain as well, tis could be oral thrush, a fungal infection. Treatment involves rinses with an anti fin gal in most cases. If there is no pain, there are a number of considerations from vitamin deficiencies to acid reflux. Only a physical exam and complete history could provide an accurate diagnosis.

Right away: A healthy tongue is not yellow. You should go see your dentist right away to see what the determining factored is and what the best course of action is.