Oral ulcers, also known as mouth sores, are common mucosal diseases in dentistry, with a high incidence, but usually heal themselves about 2 weeks after onset. Oral ulcers occur anywhere in the oral mucosa, especially on the tongue, cheeks and lips, and are usually thought to be related to genetics, immune dysfunction, stress, psychological pressure, trauma and other irritants, but the exact cause remains unclear. Oral ulcers tend to flare up periodically, hence the name recurrent aphthous ulcers. Oral ulcers are a mucosal lesion and the healing process is the healing of the mucosa, therefore they are self-healing and often take 2 weeks to heal on their own. If the onset of the disease is supplemented with local or other oral drugs to promote healing, anti-inflammatory and pain relief, it can relieve the local pain symptoms and shorten the course of the disease appropriately. You should eat a light diet, eat more vegetables and fruits, increase the intake of vitamin C foods, maintain a good state of mind and relieve stress appropriately when you have a mouth ulcer.