Pathologic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin in laboratory animals.

The technical chlorophenols and products produced from them, such as the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) have been found to contain chlorodibenzo-pdioxins such as 2,3,7,8-tetrachlorodibenzo-pdioxin (TC-DD). TCDD and other chlorodibenzo-p-dioxins are among the most toxic compounds known, and have been implicated in outbreaks of chloracne among chemical workers (1). Hepatic and cardiac lesions and thymic involution were found in rats treated with TCDD (2). Generalized subcutaneous edema, ascites, hydrothorax, and hydropericardium were observed in monkeys given toxic fat (3) which purportedly contained TCDD. It also caused focal necrosis of parenchymal cells of liver and gastric ulcers in these monkeys. The purpose of this paper is to describe the sequence of pathologic changes which occurred following exposure to TCDD in rats, guinea pigs, and mice.