To determine whether a four-month-old baby has a cold, usually look at the following aspects: 1. whether the child has typical respiratory cata symptoms, such as nasal congestion, runny nose, sneezing, coughing with phlegm, etc. 2. observe the child’s mental condition, children with a cold are usually not as lively as usual and are relatively poor in spirit. 3. pay attention to the child’s diet, children with a cold usually have a reduced appetite and may have varying degrees of nausea, vomiting, etc. 4. Observe the child’s sleeping condition, as children with colds have restless sleep, wake up easily and cry for unknown reasons. Because of the cold, especially respiratory viral infections can be nasal congestion, will cause the baby to snore at night when sleeping. 5, pay attention to the baby’s body temperature, some children with colds may have varying degrees of fever.