Baby fever usually means infection, most of them are viral infections, some are bacterial or other pathogenic infections such as mycoplasma and chlamydia, fever just a few days and fever means there may be two problems: first, the fever may not be completely controlled at the beginning, the pathogens are not completely removed, so after a few days the virus, pathogens, bacteria, etc. come back and cause another Infection fever. Secondly, the baby’s resistance and immunity are poor, and it is easy to be attacked by pathogens again, causing re-infection and fever. In either case, the fever must be checked at a regular hospital pediatric outpatient clinic or pediatric emergency room, and blood tests and C-reactive protein must be performed to understand the status of the infection and to treat the cause thoroughly, with a full course of treatment and a full dose. If it is a bacterial infection usually requires antibiotics, such as amoxicillin or cephalosporins.