Alterations produced by carbon tetrachloride in the lipids of extrahepatic tissues were studied. Consistent incorporation (about one-half of that occurring in the liver) of 14C from 14CCl4 was found in the phospholipids of the intestinal mucosa; kidney, adrenal and lung phospholipids were labeled to a lower extent, while spleen, testis, brain, heart and skeletal muscle lipids showed minor levels of radioactivity. The analysis of fatty acid methyl esters derived from phospholipids by gas-liquid chromatography (GLC) with an electron capture detector (ECD), showed ECD response similar to that observed with the liver, in the case of the intestinal mucosa and the kidney; on the contary no ECD response was seen with the organs, such as skeletal muscle, heart and testis in which the incorporation is almost negligible. Unlike liver phospholipids, the phospholipids of the intestinal mucosa and the kidney did not show diene conjugation absorption. Also, no evidence of lipid peroxidation was found in the thin-layer chromatographic analysis of fatty acid methyl esters prepared from the phospholipids of these organs. Possible meanings of these results are discussed.