The toxicity of DMDS was examined in a repeated-dose (28-day) dermal toxicity study with four groups of albino rabbits, the control and top-dose group consisting of 10 males and 10 females, and the low- and mid-dose group consisting of 5 males and 5 females. The test substance was administered daily, by dermal occlusive application. The control group was sham-treated with the occlusive dressing only. The animals of the low- and mid-dose group were treated five days a week during a four-week period, whereas animals of the top-dose group were treated with the test substance for 2 12 weeks (i.e. 13 days of treatment). The dose levels applied were 0.01, 0.1, and 1.0 ml DMDS/kg body weight/day, which is equivalent to 10.63, 106.3, and 1063 mg DMDS/kg body weight/day, respectively, and the daily exposure period was 6 hours. The study was started on April 24, 1989 and terminated on May 23, 1989.