If a child suddenly drools a lot, it is mainly due to the following reasons: First, the symptoms are caused by herpes pharyngitis, which causes herpes in the pharynx after the occurrence of herpes pharyngitis. Herpes often causes severe pain in the isthmus, as well as abdominal pain, persistent high fever, drooling, poor appetite and a series of other symptoms, which can be treated with Yinhuang pill or watermelon cream spray. Secondly, as children suffer from symptoms caused by mouth ulcers, if children have ulcers inside the mouth will also cause oral pain and drooling symptoms, you can apply heat-clearing and detoxifying drugs to relieve them, such as Pu Di Lan anti-inflammatory oral solution.