Study of the teratogenic potential of FD & C yellow No. 5 when given in drinking-water.

FD & C Yellow No. 5 was available to pregnant Osborne-Mendel rats throughout gestation at dose levels of 0.05, 0.1, 0.2, 0.4 or 0.7% in solution in distilled drinking-water. Based on fluid consumption, the rats received 67.4, 131.8, 292.4, 567.9 and 1064.3 mg FD & C Yellow No. 5/kg body weight/day. Distilled water served as the control. No dose-related changes were seen in mean daily food consumption or maternal body-weight gain. Starting during the second trimester of gestation, fluid consumption was significantly greater in the rats given 0.7% FD & C Yellow No. 5 than in the controls. The females were killed on gestation day 20. No dose-related changes were seen in maternal clinical findings, implantations, foetal viability or foetal size (weight and length). No dose-related foetal terata were seen. Neither visceral development nor skeletal development (sternebral and other skeletal bones) was affected by the dye. The small numbers of statistically significant increases in skeletal variations in the 0.05 and 0.4% levels are considered random because they are not dose related.