Patients with mouth ulcers caused by excessive internal heat can take some Chinese patent medicines that clear heat and eliminate fire. They should also drink more water, eat light meals, and consume fresh fruits and vegetables. This not only supplements various trace elements and vitamins but also enhances the body's immunity and promotes quick healing of the ulcers. The exact cause of mouth ulcers is not yet fully understood, but the disease is self-limiting and usually heals completely within about seven to ten days, so patients need not worry too much. If the ulcers cause severe local pain, lidocaine gel can be used for local treatment. Applying watermelon frost or borax powder locally can also promote the healing of ulcers.