 Leukotrienes are chemicals that are naturally made by your body. Leukotrienes are increased in the bodies of adults and children with asthma and allergies and cause some of the symptoms of these diseases. Leukotrienes are increased in the bodies of adults who have common colds and are believed to cause some of the symptoms of the common cold. It is not known if increases in leukotrienes are related to the symptoms of the common cold in children. There are also genes that may control levels of leukotrienes and other chemicals in your body during the common cold. If you enroll your child in this study, heshe will be tested for allergies and for genes that may control the levels of leukotrienes and other chemicals. 