Generally speaking, it is not advocated to use povidone-iodine to wipe mouth ulcers, which may aggravate the condition and cause gastrointestinal discomfort, as analyzed below: Povidone-iodine contains iodine, which has a certain stimulating effect on human skin and mucous membranes. The essence of mouth ulcers is that the mucous membrane has broken down, and if you apply iodized povidone on the surface of the ulcer, it may burn the mucous membrane and lead to further aggravation of the condition. In addition, povidone-iodine is a skin disinfectant and is strictly prohibited for oral use. If used in large quantities in the mouth, it may also cause gastrointestinal discomfort, such as nausea and vomiting. In severe cases of large doses, symptoms such as vomiting blood and blood in the stool may also occur. To summarize, povidone-iodine is not allowed to wipe mouth ulcers. When suffering from mouth ulcers, it should be treated with drugs such as ice borax under the guidance of a doctor.