There is a relationship between the occurrence of mouth ulcers and eating. Summarizing the personal experiences provided by patients with recurrent mouth ulcers, there are some foods listed below that may be associated with the recurrence of mouth ulcers. People refer to these foods that may cause the disease as “hairy foods”. Various kinds of pickled products: such as pickled vegetables, salted meat, salted fish, etc. Especially “old pickled vegetables”, “old salted meat”, etc. that have been pickled repeatedly or for too long. A variety of bamboo shoots and bamboo shoots products: asparagus, bamboo shoots, bamboo shoots, dried bamboo shoots, etc. Various smoked and fried foods: smoked fish, chicken, meat and fried chicken legs, fried ribs, etc. A variety of preserved products: bacon, ham, etc. A variety of fried fruit: fried peanuts, fried melon seeds, etc. As well as with a very strong stimulating chili pepper, pepper, vinegar, soju, ginger, garlic, pepper, coffee, mustard, onion, etc. Of course, “hair” often varies from person to person, and the hair that is threatening to a person A may not be harmful to a person B. Therefore, patients should not read this article and then “abstain from eating on a large scale”. The actual situation should be appropriate according to their own “taboo”, otherwise it is easy to cause nutritional disorders, no good for the recovery of mouth ulcers. The specific measures for prevention are: 1. pay attention to oral hygiene, avoid damage to the oral mucosa, avoid spicy food and local stimulation; 2. keep a relaxed mood, optimistic and cheerful, avoid things and anxious; 3. ensure sufficient sleep time, avoid excessive fatigue; 4. pay attention to regularity of life and balanced nutrition, develop certain defecation habits, prevent constipation.