To determine the metabolic disposition of [14C]‐2‐mercaptobenzothiazole (MBT) and [14C]‐2‐mercaptobenzothiazole disulfide (MBTS), male and female rats were dosed topically. Topical doses were 36.1 μg/animal for [14C]MBT and 33.6 μg/animal for [14C]MBTS. Although more MBT passed through the skin than MBTS and although, relative to rats, guinea pigs absorbed a greater percentage of the dose (33.4% compared to 16.1–17.5% of the MBT and 12.2% compared to 5.94–7.87% for MBTS), the disposition of radioactivity derived from the two compounds was similar. Washing of the skin removed more of the radioactivity from guinea pigs than from rats.