The objective of this study was to determine if exposure to divalent cations, Cd²⁺, Ni²⁺, and Co²⁺ would lead to malformations in Xenopus laevis embryos, and whether addition of Mg²⁺ and Zn²⁺; 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 Cd²⁺, Ni²⁺ or Co²⁺ lead to an increase in toxicity and teratogenicity in embryos, whereas Mg²⁺, Zn²⁺, or a combination of them reduced the toxic and teratogenic effects of these divalent cations. Modulation of Cd²⁺, Ni²⁺ or Co²⁺ toxicity and teratogenicity by Mg²⁺ and Zn²⁺, varied with the metal. Zn²⁺ was observed to be a better suppressor of Co²⁺ toxicity and teratogenicity than Mg²⁺. In contrast, Ni²⁺, and Cd²⁺ teratogenicity was reduced more prominently by Mg²⁺. On the other hand, combination of Mg²⁺ and Zn²⁺ showed potentialization effect on all divalent cation toxicity and teratogenicity. We concluded that Mg²⁺ and Zn²⁺ reduced the toxicity and teratogenicity of Cd²⁺, Ni²⁺, Co²⁺.