Lack of carcinogenicity of tragacanth gum in B6C3F1 mice.

Tragacanth gum was administered at dietary levels of 0 (control), 1.25 and 5.0% to groups of 50 male and 50 female B6C3F1 mice for 96 wk after which all animals were maintained on a basal diet without tragacanth gum for a further 10 wk. Mean body weights of females in the 5.0% and 1.25% groups were lower than those of the controls after 11 and 16 wk, respectively. However, there were no treatment-related clinical signs or adverse effects on survival rate, urinalysis, haematology, blood biochemistry and organ weight. While detailed histopathology revealed the development of squamous cell hyperplasias, papillomas and one carcinoma in the forestomach, there was no significant treatment-related increase in the incidence of any preneoplastic or neoplastic lesion. Thus, under the experimental conditions used, tragacanth gum was not carcinogenic in B6C3F1 mice of either sex.