of mortality and bladder cancer in 906 employers of a dyestuff factory in northern Italy over a mean latent period of 25 years. Mortality from bladder cancer was significantly higher in the employers than the people only exposed to the particular chemicals present in the factory, in use or intermittent contact. o-Toluidine was concluded to be almost certainly capable of causing bladder cancer in men. Another study recorder expected and observed cases of bladder cancer at a rubber factory in upstate New York (Ward et al., 1991). The study assessed 1,749 male and female employees over a period of 15 years. Exposure was primarily to o-toluidine and aniline and a significant increase in incidences of bladder cancer was observed. However, the carcinogenicity could not be attributed to o-toluidine definitively. Other studies include Vigliani & Barsotti (1961), Khlebnikova et al. (1970), Zavon et al. (1973), Conso & Pontal (1982), and Rubino et al. (1982). The specific mechanisms of carcinogenicity of o-toluidine are not completely understood, but they are known to be complex and to involve metabolic activation, which results in formation of reactive metabolites. The earlier mentioned o-nitrosotoluene, which causes cancer in rats, is an example of these reactive metabolites. Research has indicated that o-toluidine is a mutagen and causes oxidative DNA damage and chromosomal damage (Skipper et al. 2010). Multiple studies have shown that the compound induces oxidative DNA damage and strand breaks in cultured human cells (Watanabe et al. 2010; Ohkuma et al. 1999, Watanabe et al. 2010). DNA damage was also observed in rats and mice exposed in vivo to o-toluidine (Robbiano et al. 2002, Sekihashi et al. 2002) and even large scale chromosomal damage was observed in yeast and mammalian cells exposed to o-toluidine in vitro. More generally, chromosomal instability is known to be induced by aromatic amines in urinary bladder cells. Chromosomal instability may lead to both aneuploidy (presence of an abnormal number of chromosomes in a cell), which is observed in cancer cells, and loss of heterozygosity (loss of the entire gene and the surrounding chromosomal region), which can result in the absence of a tumor suppressor gene (Höglund et al. 2001, Sandberg 2002, Phillips and Richardson 2006). Specific determination of glucose o-Toluidine can also be used for measuring serum glucose concentration, in the form of acetic acid–o-toluidine. The o-toluidine reaction for the estimation of glucose concentration in the serum gained massive popularity in the