Long-term whitening of the tongue may be caused by dietary stagnation, coldness of the spleen and stomach (spleen and stomach weakness and cold), and excessive dampness. 1. Dietary stagnation: Long-term dietary irregularities, frequent consumption of spicy and oily foods, overeating and other bad dietary habits increase the burden on the spleen and stomach, causing food stagnation in the stomach and intestines, leading to obstruction of the spleen and stomach, resulting in a prolonged whitening of the tongue. 2. Spleen and stomach deficiency and cold (spleen and stomach weakness and cold): the spleen is the main organ of the body, spleen deficiency will lead to poor transportation, water metabolism is not normal, resulting in the body retaining excess water, there will also be a long-term white tongue. 3. Excessive dampness: Excessive dampness in the body over a long period of time may lead to phlegm and dampness being retained in the spleen and stomach, which can also lead to a chronically white tongue. It is recommended to consult a doctor for a clear diagnosis and targeted treatment to help improve the condition of white tongue.