The causes of gum ulcers include systemic and local factors. Systemic factors are mainly caused by a low immune system or are related to vitamin B, vitamin C and iron deficiency of trace elements. The first step is to find out the cause of the disease and treat it. You can improve your resistance by strengthening physical exercise, or eat more foods rich in vitamin B and vitamin C. You can also eat more foods rich in iron, and in case of serious iron deficiency, you need to take oral liquid for iron supplementation. If there are local traumatic factors in the mouth, such as sharp tooth tips or root remnants, which can cause traumatic ulcers, the first step is to remove the crown remnants and round off the sharp tooth tips to remove the irritating factors. Localized gum ulcers can be relieved by using pain relieving films or by applying iodine glycerin after cautery to promote healing. Some gum ulcers are also caused by bad habits, such as biting into mucous membranes or mechanical irritation, which should first be removed and then treated with local symptomatic treatment of the gums. Therefore, gum ulcers can be treated symptomatically by improving the immune system to improve the symptoms or by removing the irritation and using topical pain-relieving films.