Use of the mouse spot test to investigate the mutagenic potential of triclosan (Irgasan DP300).

Triclosan, a chlorophenoxyphenol used in several commercial products, was tested in the mouse in vivo somatic mutation test (spot test) by intraperitoneal injection on day 9.25 or 10.25 postconception. Although the dose range tested overlapped the toxic, the frequency of presumed somatic mutations was not significantly greater in the experimental groups than in the methanol-injected controls; and the results rule out with 95% confidence a spot incidence 5 or more times greater than the control incidence. These findings fail to confirm the claim by Fahrig et al. (1978) that triclosan is mutagenic in the spot test.