The baby’s mouth has a sour odor, mostly considered improper feeding, abuse of antibiotics, indigestion, gastroenteritis and other reasons caused by the need to go to the hospital for examination, to determine the cause and then treatment. 1, dietary factors: eating too much, too fast, eating too much indigestible or sweet food, resulting in difficulty in timely digestion, will remain in the gastrointestinal tract, coupled with parents do not pay attention to the baby’s oral hygiene, resulting in food residues fermentation for a long time produce sour odor. Lighter cases can be hot compresses or massage, adjust the bad eating habits; more serious cases can follow medical advice to the stomach to eliminate food tablets, probiotics. And improve the bad feeding, take a small number of times the diet, while giving the baby daily oral cleaning care; 2, drug factors: if due to some infectious diseases, without medical advice for a long time, a large number of children blindly take antibiotics, can lead to gastrointestinal flora imbalance, causing the baby’s mouth sour odor. The use of antibiotics must strictly follow medical advice, prohibit abuse; 3, disease factors: often caused by gastrointestinal inflammatory lesions, due to infection with certain microorganisms or bacteria, gastrointestinal flora imbalance, digestion of food will have corrupt gas, up to the mouth easily lead to bad breath, accompanied by diarrhea, abdominal pain and other symptoms. It is recommended to seek medical attention and follow medical advice to give medication, mostly symptomatic treatment, such as diarrhea can be applied montelukast, water-electrolyte disorders can be oral rehydration salt. If your baby’s mouth has a sour smell, parents can let your baby drink more water, eat a light diet, eat more fresh vegetables and fruits, and pay attention to oral hygiene, develop the good habit of brushing teeth before bedtime and in the morning, and rinsing mouth before and after meals.