The objective of this study was to aid the assessment of the systemic toxic potential of Dow Corning 200(TradeName) Fluid, 350 cSt in a 28 day dermal study in the rabbit. The study was performed in general compliance with the United States Environmental Protection Agency Guideline 798.2250 (Toxic Substances Control Act, September 1985; revised through 1 July 1991; amended 19 June 1995), 'Dermal Toxicity Study for 90 days'. Some aspects of this guideline were modified to be appropriate for a 28 day dermal toxicity study in the Rabbit. Dow Corning 200(TradeName) Fluid, 350 cSt was administered by dermal application to three groups of 10 male and 10 female New Zealand White rabbits for four weeks at dosages of 100, 300 or 1000 mg/kg/day. The test substance was removed after six hours of exposure on each day of treatment. A similarly constituted fourth group, serving as Controls (Sham Controls), were subjected to the same procedures as the treated animals, but no test substance was applied. Throughout the study the animals were observed daily for signs associated with treatment. Before each administration the dermal test site was examined for signs of irritation. Bodyweights were determined twice each week and food consumption once each week. Blood samples were taken for haematology and blood chemistry investigations-on Day 29 for males and Day 30 for females. After a minimum of 29 days of treatment the animals were sacrificed and subjected to a full macroscopic examination. Selected organs were weighed and tissues were processed and examined microscopically. There were no deaths and no adverse signs considered to be related to treatment. Ungroomed coat for animals receiving 300 or 1000 mg/kg/day was considered to be a result of the accumulation of test substance around the application site.