Nine-year-old child vomiting and diarrhea fever, the possible causes include gastrointestinal cold, acute gastroenteritis and other diseases. 1. Gastrointestinal cold: Its main cause is viral infection, including respiratory syncytial virus. Symptoms such as vomiting, diarrhea, and fever may occur, along with headache, nasal congestion, and runny nose. 2. Acute gastroenteritis: its causes are complex, including viral infection, bacterial infection, unclean diet, etc. Symptoms are mainly diarrhea, vomiting, nausea and other symptoms, and fever can occur in severe infections. In addition, meningitis, pneumonia, inflammatory bowel disease, etc. may also lead to vomiting, diarrhea, fever and other symptoms. If you experience any of the above symptoms or suspect gastrointestinal flu, acute gastroenteritis, meningitis, etc., it is recommended that you go to the hospital promptly.