Corrosion protection efficiency of gum exudates of Astragalus genus (AG) on mild steel surface in 1N HCl medium was investigated using potentiodynamic polarization and electrochemical impedance spectroscopic measurements. The results show that AG acts as an effective green inhibitor for mild steel corrosion in 1N HCl and their inhibition efficiency increases with increasing concentration. Tafel’s measurements showed that AG behaves as a mixed-type inhibitor with a predominant cathodic character. The impedance parameters confirm that AG is adsorbed in the form of a protective film on the mild steel surface. The DFT theory at the B3LYP/6-31G (d) basis set level was also performed for the identification of active constituents of AG to investigate the correlation between their molecular structure and corrosion protection efficiency