ABSTRACT
Both metallic thallium and water-soluble thallium salts are highly toxic. Unlike the other group IIIA metals, thallium does not precipitate as an oxide at physiological pH. Of the two main valences, Tl1 and Tl3, the monovalent (thallous) salts are the more toxic, yet for a period they were used therapeutically in human medicine. Following dermal, parenteral, or oral absorption, the metal is rapidly distributed throughout the body tissues, and over time accumulates due to its slow rate of elimination (1). Because of the severe toxicity of thallium salts, the use of these salts for medicinal purposes was halted in the early 1900s (2).
