What causes a yellow, thick, and greasy tongue coating, and how can it be managed?

Generally, a thick, yellow, and greasy tongue coating may be caused by factors such as improper diet, poor oral hygiene, excessive internal heat ("fire"), damp-heat in the spleen and stomach, or intestinal damp-heat. These conditions can be improved through dietary adjustments, better oral hygiene, and medical treatment. If symptoms persist, prompt medical consultation is recommended. Detailed explanations are as follows:

1. Improper Diet: Long-term or excessive consumption of spicy and stimulating foods such as chili peppers, ginger, and garlic may disrupt gastrointestinal digestive function, impairing the normal function of the spleen and stomach and leading to internal damp-heat. This may manifest as a yellow, thick, and greasy tongue coating. A bland and easily digestible diet, such as millet porridge and noodles, is recommended.

2. Oral Hygiene: Insufficient oral cleaning may lead to bacterial buildup and food residue on the tongue surface, which can also cause a thick, yellow, and greasy tongue coating. Using a tongue scraper or a soft-bristled toothbrush to gently clean the tongue can help remove surface bacteria and food residue.

3. Excessive Internal Heat ("Fire"): Internal heat may be triggered by emotional stress, consumption of irritating foods, or staying up late. It may lead to a thick, yellow, and greasy tongue coating, often accompanied by symptoms such as dry mouth and bitter taste. Medications such as Tianwang Buxin Dan (Heavenly King Heart-Nourishing Pill), Yangyin Qingfei Wan (Nourishing-Yin and Clearing-Lung Pill), or Niuhuang Qingfei Pian (Bezoar Anti-Heat Lung Tablet) may be taken under a doctor's guidance to alleviate symptoms.

4. Damp-Heat in the Spleen and Stomach: Damp-heat in the spleen and stomach may be related to improper diet, which can impair the digestive and transforming functions of the spleen and stomach, resulting in internal damp-heat. Symptoms may include a thick, yellow, and greasy tongue coating, along with poor appetite and abdominal distension. Medications such as Shenling Baizhu San (Dioscoreae and Poria Powder) or Xiangsha Yangwei Wan (Fruit and Rhizome Stomach-Nourishing Pills) may be used as directed by a physician.

5. Intestinal Damp-Heat: Intestinal damp-heat is often caused by consumption of unclean food or external contraction of damp-heat pathogens, leading to dysfunction of the intestines. Damp-heat accumulating in the intestines can affect normal bowel function, causing damp-heat to manifest on the tongue, resulting in a thick, yellow, and greasy tongue coating. Symptoms may also include bitter taste in the mouth and constipation. Treatment options may include medications such as Gandan Shuangqing Granules (Liver and Gallbladder Dual-Clearing Granules), Xiongdan Kaiming Pian (Bear Gallbladder Eye-Brightening Tablets), or Kutai Granules, used under medical supervision.

In daily life, maintaining a healthy lifestyle—including a bland diet, moderate exercise, and sufficient sleep—is beneficial for overall health.