Percutaneous acute toxicity of octamethylcyclotetrasiloxane (D4) in the rat. Sprague-Dawley rats of OFA(IOPS) strain weighing 180 - 200 g were used. Results of the range finding test is as follows: Two groups of 4 animals (2M,2F per group) were used at doses of 1000 mg/kg and 2000 mg/kg. The animals were closely clipped 24 hours before application on the whole dorsal zone. The product was applied as is (D0) on the dorasl zone and lightly spread on the skin. A bandage made of aluminum foil is immediately held over it by an adhesive strip. The animals were observed 24 hours following the application (D1). The bandage was removed andthe application zone was not rinsed. The animals were then observed for 14 days. No mortality was observed in any of the animals. Resutlts of the definitive test is as follows: Based on the results of the preliminary study a group of 10 animals (5M,5F) received the product under the same conditions above at a dose of 2000 mg/kg. A control group of 10 animals (5M,5F) were used under the same conditions but without application of the product. The behavior and mortality were observed after administration of the product, then again 1, 2, and 6 hours each day for the following 14 days. The local tolerance was noted. The animals body weights were also measured on days 0, 1, 2, 4, 7, and 15 days. Results of treatment for the following 14 days included no behavioral abnormalities. The local tolerance of the product was good. No cutaneous lesions were noted. Under the experimental conditions above, octamethylcyclotetrasiloxane (D4) applied is non-toxic percutaneously in the rat at a dose of 2000 mg/kg.