Polymeric blends between chitosan and poly(epichlorohydrin) (PECH) modified with sodium hydrogen squarate were prepared by the casting method, using formic acid (85%) as the solvent. The compatibility of the blends was studied by different methods, such as Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetric analyses. Cytotoxicity assays were also performed by the direct contact method to assess the feasibility of using these materials in veterinary devices. Based on the analysis results, we concluded that these polymers are compatible due to the interaction between the NH3+ chitosan groups and CO- groups of the modified poly(epichlorohydrin), as well the hydrogen bond between the chlorine atom of the modified poly(epichlorohydrin) and the hydrogens of the chitosan methyl group. It is important to highlight that electrostatic interactions are also responsible for the non-toxicity of these materials in bovine fibroblast cells, which indicates the feasibility of their use in veterinary devices for cattle.