CCl₄-damaged rat liver cells have a number of nucleases, one of which has been partial~y purified. The partially purified nuclease is optimal in its activity around pH 9.6 and hycrolyzes heat -denatured DNA more rapidly than native DNA, exhibiaing the ratio of acid to alkaline activity of 0.3. Evidence indicates that nucleases from CCl₄-damaged rat liver cells are different from those from normal liver cells. It may, therefore, suggest that nucleases from CCl₄-damaged rat liver tells may be responsible for some metabohe deterioration observed following CCl₄ hitoxication,