Children with bad breath and bad odor may be related to oral hygiene, oral diseases, respiratory and digestive problems. 1. Oral hygiene problems: some children do not like to brush their teeth, parents do not supervise enough will lead to children’s teeth left a lot of food debris, food debris in the oral cavity fermentation and corruption will have an unpleasant odor. 2. Oral disease: in addition to the oral cavity is not timely clean, some stomatological diseases can also lead to the occurrence of bad breath, such as gingivitis, dental caries, etc., this time by the oral cavity of anaerobic bacteria decomposition of proteins, peptides and amino acids, resulting in volatile sulfide. 3. Respiratory problems: children with sinusitis, pharyngitis, etc. can also lead to the occurrence of halitosis, because the nose, throat and oral communication, so the nasal cavity, pharynx, inflammatory secretions of the unpleasant odor will also lead to halitosis. 4. digestive problems: children’s digestive ability is weak, and some parents are afraid of treating their children, often fish and meat to the children to eat, the children appear indigestion, food accumulation in the stomach fermentation is very easy to appear bad breath. There are many other reasons for children’s bad breath, it is recommended to go to the hospital for a formal examination to clarify the cause of the disease after targeted treatment.