Study background: adding Smyrnium cordifolium nanoparticles and milk thistle essential oil can improve the physicochemical properties of films based on alfalfa seed mucilage. Purpose: The purpose of this study was to prepare edible films from alfalfa seed mucilage with Smyrnium cordifolium nanoparticles (0, 2, 4%) and milk thistle essential oil (0, 1, 2%). Methodology: Edible films based on alfalfa seed mucilage were prepared and Smyrnium cordifolium nanoparticles (0, 2, 4%) and milk thistle essential oil (0, 1, 2%) were added to it. The physicochemical properties of the prepared films were investigated. Results: According to the obtained results, increasing the amount of Smyrnium cordifolium nanoparticles and milk thistle essential oil in the film decreased the mechanical properties of the films. The results of antimicrobial activity showed that the addition of Smyrnium cordifolium nanoparticles increased the activity of the film against Staphylococcus aureus. The dynamic light scattering (DLS) results confirmed the Smyrnium cordifolium nanoparticles. Fourier transform infrared (FTIR) results confirmed the physical presence of Smyrnium cordifolium nanoparticles in the polymer matrix. The increase of Smyrnium cordifolium nanoparticles and milk thistle essential oil in the films could delay the thermal decomposition of alfalfa seed mucilage and increase the thermal stability of the mucilage film. Final conclusion: Adding Smyrnium cordifolium nanoparticles and milk thistle essential oil to edible films based on alfalfa seed mucilage improved the antimicrobial, Fourier infrared (FTIR) properties of the films, and also weakened the mechanical properties.