Previous studies have demonstrated that athletic mouthguards worn by ice hockey and football players harbor large numbers of bacteria, yeasts, and molds, some of which are either opportunistic or frank pathogens. This article details the clinical history of two junior high school football players. The first player had cellulitis of the leg after a non-break injury. The same unusual bacterium was isolated from both the athletic mouthguard and abscess cultures from the wound. The second patient suffered an attack of exercise-induced asthma so severe that his inhaler could not control the symptoms enough for him to resume play. This child's mouthguard was contaminated with five different species of mold. The clinical implications of mouthguard contamination, possible avenues of disease transmission, and recommendations for mouthguard care are discussed.