In recent decades, efforts to find sustainable green solutions and replace conventional packaging materials with natural resources have increased. In the present research, the influence of methanol extract from Eryngium billardieri (0, 1, 3, and 5%) on some physico-mechanical properties and antibacterial activity of sago starch films was investigated. The results showed that increasing the extract concentration resulted in a significant (P 0.05) increase in the films' water absorption capacity (1.883.16 g water/g dry film) and water vapour permeability (1.6310-112.3210-11 g/m s.s.Pa).The solubility of the films in water was obtained to be in the range of 18.21‒18.53%, and increased slightly with increasing the extract concentration. Tensile strength and Young’s modulus changed in the range of 13.11‒19.34 MPa and 100.14‒115.25 MPa, respectively. Compared to the control film, the composite films represented more flexibility, and the elasticity was continually enhanced with an increasing percentage of the extract. Both gram-positive and gram-negative bacteria were resistant to the films' antimicrobial activity. Based on the results obtained in this study, due to the improved properties of the sago starch film, the composite films could be effectively used in the production of the capsule shell materials.