A common cold is usually a virus-induced, acute infection of the upper respiratory tract. This type of respiratory infections are among the most common diseases in modern industrial countries. On the average adults suffer up to five times a year a cold, preschoolers even eight to ten times. In most cases the infections are caused by viruses and associated with similar symptoms: shivering, sneezing, runny nose, cough and fatigue. Since antibiotics work only in the treatment of bacterial infections, applying them in case of infections of viral origin, they might remain ineffective.