Does a white tongue mean you are sick?

White tongue is usually caused when bacteria, debris (like food and sugar) and dead cells get trapped between the papillae on the surface of your tongue. These string-like papillae then grow large and swell up, sometimes becoming inflamed. This creates the white patch you see on your tongue. But on rare occasions, this symptom can warn of a more serious condition like an infection or early cancer. That's why it's important to keep an eye on your other symptoms and call your doctor if the white coating doesn't go away in a couple of weeks.