Mucosal leukoplakia is a white patch or plaque on the oral mucosa, and it is called oral mucosal leukoplakia when it cannot be diagnosed as other diseases by histopathological methods. Oral mucosal leukoplakia is usually a precancerous lesion, however, it may not always turn into cancer, so when oral mucosal leukoplakia appears, it should be actively treated. Oral mucosal leukoplakia may be caused by local irritants, or it may be produced by smoking or frequent consumption of excessively hot or spicy, irritating foods that can increase the incidence of leukoplakia. In addition, the white spots may also be caused by oral Candida infection. Therefore, if white spots of oral mucosa appear, first of all, local irritants such as sharp tooth tips or residual roots and crowns should be removed. It is better to avoid smoking, alcohol, spicy and irritating food to control oral Candida infection. If cancer is suspected, surgical removal and pathological test should be done in time.