It is possible to apply Yunnan Baiyao powder to mouth ulcers. From clinical observations, some mouth ulcers heal faster with the application of Yunnan Baiyao powder, but it should be noted that mouth ulcers only increase the healing rate of patients with mouth ulcers and do not immediately cure them or even stop recurrent mouth ulcers from coming back. Because mouth ulcers are self-limiting, they will heal naturally in about 1-2 weeks without special treatment, but they are characterized by frequent recurrence. Yunnan Baiyao, from clinical observation, can relieve some patients of their mouth ulcers for a long time, but it does not have a particularly good therapeutic effect on mouth ulcers.