To evaluate possible teratogenicity of food additives such as sodium propionate and monosodium glutamate, 300 haching eggs were subjected to potential mutagenicity assay by administration of low and high doses of the materials via york and air sac. The results are summarized as follows: 1. Mortality rate of chick embryo was increased significantly by dosage related in the group of sodium propiorate and monosodium glutamate when compared to placebo and non-treated group. 2. Frequency of embryo with malformation in treated group was not increased significantly when compared to placebo and non-treated group.