Evaluation of the teratogenic potential of tertiary butylhydroquinone (TBHA) in the rat.

Tertiary butylhydroquinone (TBHQ), and approved antioxidant used alone or in combination with other antioxidants produced no teralogenic effects after administration via the diet to pregnant rats at concentration of 0.125, 0.25 and 0.50% during the sensitive period of gestation. The mean body weight and feed consumption of the dams were unaffected. The average number of corpora lutea, implantation sites, viable fetuses, resorptions and fetal body weights and mortality did not differ between the control and treated groups. A significant number of rudimentary ribs were seen in all groups. However, the incidence of this variation was two times greater in the control group than in any treatment group. It is concluded that TBHQ is not teratogenic in rats at 62.5, 125 and 250 times the approved use level for humans.