The most likely cause of oral mucosal whitening is oral submucosal fibrosis. Oral submucosal fibrosis is mainly manifested as pale or off-white lesions in the buccal, soft palate, lips, tongue, gingival mucosa, etc., followed by opaque, lusterless fibrous stripe-like damage in the submucosa. Patients often complain of burning pain in the oral mucosa, especially when eating irritating foods, and symptoms such as dry mouth, ulcers, and loss of taste. As the disease worsens, patients may have difficulty in opening the mouth, pronunciation and swallowing due to the gradual stiffening of the mucosa. Another possibility is the white spots of oral mucosa, and the white spots usually appear in the mouth of patients who have been chewing betel nut or spicy irritating food for a long time; it may also be caused by local irritation factors, such as local root remnants, crown remnants, or bad restorations, which stimulate the oral mucosa, and such long-term stimulation will easily lead to the occurrence of oral white spots. The first treatment is to quit chewing betel nut, tobacco and alcohol and other bad habits, so as to facilitate the recovery of the oral mucosa; for those who suspect malignant changes, surgical removal and pathological examination.