If a four year old baby develops mouth ulcers, there is no need to be particularly worried. The first thing to do is to see if the child had symptoms of fever, elevated body temperature, and blisters on the mouth prior to the occurrence of the mouth ulcers. If there are symptoms similar to these, it may be caused by a herpes simplex infection. Mouth ulcers occur when the blisters rupture after a viral infection. Antiviral treatment is needed at this time, such as oral scutellaria baicalensis oral solution, drink plenty of water, and after the blisters rupture and form ulcers, you can spray children’s open-throat sword spray on the local area. If there is no such symptom, just simple mouth ulcers, about 15 days will be automatically healed, can also be sprayed in the local open throat sword spray, gargle with mouthwash, can reduce the pain, promote the healing of ulcers, and to prevent ulcers from becoming infected.