Mononucleosis or Mono, is a viral illness. We see it in two clinical situations in our office. First of all, as commonly known, we see it in teenagers and is known as the kissing disease; which is a bit of a misnomer because it is probably not passed by kissing. We also see it in younger children, who may present to the office with a fever that lasts longer than three or four days, and tonsillitis, with a white exudate on their tonsils. In both of those situations, antibiotics are not helpful since this is a viral illness. The treatment is mostly supportive. In most children and teenagers with Mono, the disease will run approximately one to two weeks, rarely longer.