Bad breath in babies is usually divided into two kinds: physiological bad breath and pathological bad breath. Usually the causes of bad breath in babies are poor oral hygiene, dry mouth, indigestion, oral ulcers, respiratory diseases and so on. Usually baby halitosis can be prevented by paying attention to oral hygiene, drinking more water and taking medicine. 1, pay attention to oral hygiene: brush your teeth is the most effective way to maintain oral hygiene and keep away from bad breath. However, babies under one year old cannot brush their teeth. For babies under one year old, mothers can use gauze dipped in warm water to clean the baby’s mouth; babies over one year old are recommended to rinse their mouth with warm boiled water or light salt water every night; babies over two years old can learn to brush their teeth by themselves. 2, drink more water: drink more water can keep the baby’s mouth moist and clean environment, reduce oral diseases, it is recommended that the mother supervise and train the baby to drink more cool boiled water habit. 3, take medicine: If the baby’s bad breath is caused by indigestion, periodontitis, dental caries and other diseases, it is recommended to take the baby to the hospital for examination, and then targeted treatment and drug conditioning, but be careful not to abuse drugs, must be under the guidance of the doctor reasonable use of drugs. If your baby has persistent bad breath, you should go to the hospital in time, and you should also protect your oral hygiene in daily life.