Hello, you said the situation is very normal, most of the causes of bad breath lies in the stomach and intestines, bad breath is just a reflection of the stomach and intestines, given that your daughter is too small, do gastrointestinal examination is not good after all, so you can give her dietary modification for a period of time, during the modification of spicy stimulation can not be eaten, drink plenty of water, more vegetables and fruits, and in the morning and evening, you can drink more millet porridge and other fluid food, it's very good to eat the stomach. The most important thing to remember is that you should not eat anything spicy or stimulating during the period of regulation. This kind of conditioning for a period of time should have the effect. I wish your daughter a speedy recovery.