Children’s bad breath is particularly serious may be periodontitis, dental caries, peptic ulcers and other diseases. 1. Periodontitis: children with particularly bad breath may be plaque infection caused by chronic inflammation of the periodontium, patients will also bleed when brushing, gums red and swollen. 2. Dental caries: also known as caries, bacterial infection caused by the destruction of dental tissues, patients will have bad breath, acid, sweet and other stimuli have pain, if necessary, surgery. 3. Peptic ulcer: children with particularly bad breath may also be caused by Helicobacter pylori infection resulting in peptic ulcer, the patient will also have regular abdominal pain, acid reflux, belching (hiccups). Children’s bad breath is particularly serious, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.