A white tongue means there is a white coating or film on the top surface of the tongue. This coating is usually caused by a buildup of bacteria, dead cells, food debris, or fungi trapped between the small bumps (papillae) on the tongue. It often indicates poor oral hygiene, dry mouth, dehydration, smoking, alcohol use, or mouth breathing. In most cases, a white tongue is harmless and temporary. However, if the white coating lasts longer than a few weeks or is accompanied by pain, difficulty eating or talking, it could be a sign of an underlying health condition such as oral thrush (a fungal infection), leukoplakia (white patches that cannot be scraped off), lichen planus (a chronic inflammatory condition), or even precancerous changes. In these cases, medical consultation is advised. In summary, a white tongue generally suggests trapped bacteria or debris, often related to hygiene or dryness, but it can sometimes indicate infections or other health issues requiring a healthcare provider's evaluation.