There are still many reasons why an eleven-month-old baby may have fever. Rheumatic immune system diseases can cause fever in babies, and blood system diseases can also cause fever in babies. However, these two types of diseases tend to be relatively rare. In general, most of the symptoms of fever in babies occur as a result of viral or bacterial infections, most likely caused by a cold. Symptoms accompanied by nasal congestion and runny nose are often due to a cold virus multiplying in the child’s body, stimulating the child’s thermoregulatory center and causing the temperature regulating point to move up, resulting in fever. The use of cold and flu medications or antiviral medications are more effective. The antiviral medication can be chosen from the Four Seasons Antiviral Combination or Pudilan Anti-inflammatory Oral Liquid; the cold medication can be chosen from Pediatric Cold and Flu Clear Fever Granules or Pediatric Black Ciao Clear Fever Granules. If the fever is higher than 38.5 degrees, you need to give your baby oral ibuprofen suspension to reduce fever.