The objective of this study was to determine if exposure to divalent cations, Cd(2+), Ni(2+), and Co(2+) would lead to malformations in Xenopus laevis embryos, and whether addition of Mg(2+) and Zn(2+); separately and in combination, would reduce their toxicity and teratogenicity on the embryos of Xenopus laevis as assessed by 96-h FETAX tests. Results indicate that exposure to Cd(2+), Ni(2+) or Co(2+) lead to an increase in toxicity and teratogenicity in embryos, whereas Mg(2+), Zn(2+), or a combination of them reduced the toxic and teratogenic effects of these divalent cations. Modulation of Cd(2+), Ni(2+) or Co(2+) toxicity and teratogenicity by Mg(2+) and Zn(2+), varied with the metal. Zn(2+) was observed to be a better suppressor of Co(2+) toxicity and teratogenicity than Mg(2+). In contrast, Ni(2+), and Cd(2+) teratogenicity was reduced more prominently by Mg(2+). On the other hand, combination of Mg(2+) and Zn(2+) showed potentialization effect on all divalent cation toxicity and teratogenicity. We concluded that Mg(2+) and Zn(2+) reduced the toxicity and teratogenicity of Cd(2+), Ni(2+), Co(2+).