A 3-year-old child’s mouth ulcers can be treated with general treatment such as strengthening nursing care and medication such as Guilin watermelon cream tablets. 1. General treatment: should strengthen the care of the child, pay attention to rest, ensure sufficient sleep. Attention should be paid to keep the mouth clean, drink a lot of water, to the temperature of the appropriate semi-liquid food is appropriate, should avoid spicy and other stimulating food. 2. Medication: Mouth ulcers can be treated locally with Guilin watermelon cream tablets, tin-like bulk and other drugs. If the pain is severe, you can use lidocaine and other drugs to smear. If the mouth ulcer is accompanied by infection, can use amoxicillin and other antibiotic drugs for treatment. The use of specific drugs should be under the guidance of the doctor, avoid self-medication. If the child’s mouth ulcers are serious, or persistent and have not improved, they should go to the hospital in order to clarify the cause of the disease and standardize the treatment.