When germs that cause colds first infect the nose and sinuses, the nose makes clear mucus. This helps wash the germs from the nose and sinuses. After two or three days, the body's immune cells fight back, changing the mucus to a white or yellow color. As the bacteria that live in the nose grow back, they may also be found in the mucus, which changes the mucus to a greenish color. This is normal and does not mean you or your child needs antibiotics.
Over 200 viruses can cause the common cold
The rhinovirus is the most common type of virus that causes colds
Preventing the Common Cold
Practice good hand hygiene
Avoid close contact with people who have colds or other upper respiratory infections
Wipe down commonly touched surfaces