The toxicity of Pluronic F-68, a non-ionic polyol, was studied in the rat when administered intravenously for one month in daily doses of 0, 10, 20, 50, 100, 200, 500 and 1000 mg/kg. Pluronic F-68 induced pulmonary foam cells at the dose levels of 500 and 1000 mg/kg and slight focal degenerative changes in the proximal tubules of the kidneys at the dose levels of 100, 200, 500 and 1000 mg/kg. The cytoplasm of the pulmonary foam cells contained lipid droplets, phospholipids being the most essential constituent. The results indicate that Pluronic F-68 is able to induce phospholipidosis in the rat. Only drugs have so far been reported to cause this condition in the rat.