What does it mean when the tongue coating is white and thick?

A thick, white tongue coating may be caused by various factors. Poor oral hygiene, with excessive food debris and bacteria remaining on the tongue surface, can lead to a thickened tongue coating. Common causes also include spleen and stomach damp-cold, food stagnation, and internal heat ("fire"). Spleen and stomach damp-cold may result from insufficient yang energy, prolonged exposure to cold and damp environments, or excessive consumption of raw or cold foods. Food stagnation may arise from indigestion or overeating sticky, greasy, or rich foods. Internal heat may be associated with emotional instability, irritability, chronic anxiety, and stress. Additionally, deficiencies in both qi and blood, as well as spleen and stomach deficiency-cold, may also contribute to a thick, white tongue coating. It is recommended to maintain good oral hygiene, adjust dietary habits, and seek medical treatment when necessary.