Chemical insult to the skin or the enteric tract is reviewed. The manner in which chemical agents destroy tissue is described. It is noted that as a class these chemicals coagulate protein by reduction, oxidation, salt formation, corrosion, protoplasmic poisoning, metabolic competition and inhibition, desiccation, or the ischemic components of vesicant activity. The actions, toxic potential, and basic emergency therapy for various chemical agents that harm the skin or the enteric tract are summarized. Oxidizing agents such as chromic-acid (7738945), sodium-hypochlorite (7681529), and potassium-permanganate (7722647) are discussed. Reducing agents including alkyl mercuric agents, hydrochloric-acid (7647010), and nitric-acid (7697372) are considered. Corrosive agents including the phenols and cresols, white-phosphorous, dichromate salts, sodium metals, and the lyes are addressed. Among the protoplasmic poisons, the alkaloidal acids, acetic-acid (64175), formic-acid (64186), and the metabolic competitors and inhibitors are examined. Sulfuric-acid (7664939) and muriatic-acid (7647010) are described in the section on the desiccants. Cantharides, dimethyl-sulfoxide (67685), mustard-gas (505602), and lewisite (1306021) are considered in the discussion of the vesicants.