It is not normal for a 2.5 year old baby to drool a lot, exclude the presence of oral diseases or indigestion and other reasons. 1. Oral diseases: baby oral diseases such as uveitis, mouth ulcers, can stimulate the salivary glands and thus cause the phenomenon of drooling, baby uveitis, pay attention to eat warm and soft easy to digest food. 2. Indigestion: When babies suffer from indigestion, it may stimulate the secretion of gastric acid to increase, which may cause drooling. Pay attention to adjust the diet structure, avoid eating too much, avoid eating too much greasy food. 3. Other: When babies drool, it is necessary to rule out the existence of central nervous system underdevelopment and abnormal IQ development, etc. Parents are advised to bring their children to the doctor in time for standardized and professional examination.