In early spring, some people will have lip erosion or ulcers, which is medically called “stomatitis”, commonly known as “rotten mouth”. This is mostly due to vitamin B2 deficiency in the body. “The first time the skin junction of the mucous membrane of the corner of the mouth is white or pale; then the lesion area becomes soft and soft, and there is irritation and pain when opening the mouth; then there are ulcers, dry and cracked bleeding, often with secondary infections, and sometimes small pustules and crusts, with pain, and inability to open the mouth when talking and eating. Depending on the cause, keratitis can be divided into dystrophic keratitis, coccidial keratitis, and fungal keratitis, of which dystrophic keratitis is the most common. Therefore, the prevention of “rotten mouth” should start from the following points. 1, pay attention to adjusting the diet, do not be partial food. Eat more green fresh vegetables, radishes, carrots and various fruits, and appropriately increase soy products, eggs, lean meat, animal liver and other foods rich in B vitamins to prevent riboflavin deficiency. 2, pay attention to facial hygiene and nourishing health care. After meals should be washed in a timely manner, the corners of the mouth dry; cold and dry when the local should often smear some emollient cream, lips and corners of the mouth dry skin, you can apply anti-cracking oil, such as petroleum jelly, cod liver oil or greasy skin cream, but do not rub glycerin, because glycerin is not grease, it has a dehydrating effect, will make the skin dry. 3, develop the habit of drinking boiled water regularly, which is conducive to improving the moisturizing degree of the body and skin. If you drink water only when your mouth is dry, it will lead to the lack of water in the organism. 4.Actively treat the disease of excessive salivation and drooling, and correct the bad habit of licking the corners of the mouth frequently. If corns of the mouth have occurred and dry and cracked and bleeding, the trauma should first be washed with warm water or salt water, and after drying slightly, then smear antibiotic ointment, such as gentamycin eye ointment, or use cod liver oil riboflavin paste, and take riboflavin orally. When the trauma surface starts to crust, do not forcibly tear off the dried scab, but let it fall off after self-healing. At the same time, vitamin B2 and vitamin C can be taken, and topical medications such as gentamycin ointment can be applied.