Occlusions are also a type of acne and belong to whiteheads. The growth of acne is related to the lack of attention to skin cleanliness and improper diet, and excessive dry skin is also related to acne. In addition, long-term use of cosmetics and endocrine disorders, such as androgen elevation and vitamin deficiency, are all related to acne, as are diet, rest, sleep, and mood factors. Therefore, to prevent the occurrence of xerostomia should pay attention to local skin care, pay attention to personal hygiene, eat more fresh fruits and vegetables, eat more easily digestible food, and try to eat less onion, ginger, garlic, chili, sweets, milk tea and other foods. In addition, do not stay up late, should ensure sufficient sleep, keep a relaxed mood, can properly participate in outdoor activities, the above is about the causes of long closed mouth and common precautions.