As long as the immunity of the baby’s body is relatively normal and the symptoms of the cold are not very serious, after 5-7 days the baby’s cold can be cured by itself. During the first three days of the cold, the virus is very active and invades the mucous membrane cells of the nose or throat, which results in nasal congestion and runny nose, and systemic symptoms may follow, such as weakness or pain in the muscles or bones of the body. After three days of having a cold, the body’s immune system recognizes the cold virus and begins to fight it. It is possible that the symptoms of this process will worsen, including the appearance of fever, increased cough, and increased amount of nasal discharge and phlegm, and that the symptoms will not behave in the same way depending on the immune system. In the later stages of the cold, about 5-7 days, thicker nasal discharge and phlegm will occur.