Mercury has a number of unique and fascinating properties. It is present in the environment in several forms, both organic and inorganic. Each of these forms has somewhat unique properties that differentiate them from the other forms, but all are toxic to humans in one way or the others. Mercury has been proven to be a potential source of poisoning in children as a result of the inappropriate handling of a liquid mercury. The cases of metallic mercury vapor intoxication not associated with occupational exposure may occur in school science laboratories, from mercury dust and powders, from latex paint containing a mercury-based fungicide, and from normal wear or installation of dental amalgam fillings. Another source of toxic mercury exposure can be broken thermometers, barometers, or sphygmomanometers that may occur in the home, and children are often victims of environmental exposure. In this paper, we present three members of a family who were exposed to mercury brought home from school by a family member. Since the mercury exposure was not known, the initial presentation and clinical picture suggested a misdiagnosis, a contagious infectious disease, because the onset of symptoms occurred at different times in the same family members. A subsequent change to a diagnosis of mercury intoxication and chelation therapy with meso-2,3-dimercaptosuccinic acid was started.