**Abstract**

We highlight in this chapter the corrosion protection using phenolic extract. The building of mathematical models using experimental results obtained from the investigation of phenolic molecules or fractions extracted from *Echium italicum* L., used as corrosion inhibitors is one of the new trends in the study of steel protection. The evaluation of the corrosion inhibition of carbon steel (API 5 L-X60) in a solution 1 M of hydrochloric acid was performed using gravimetric method, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The predicted mathematical relationships between the corrosion rate and the inhibitory efficiency in the presence of the butanolic extract of *Echium italicum* L. (BEEI), when increasing temperature proved a good agreement between experimental and mathematical studies.

**Keywords:** mathematical, relationship, *Echium italicum* L., phenolic compounds, corrosion inhibition
