Ethyl acetate extract (EAE) and butanolic extract (BE) of Thapsia villosa were investigated as corrosion inhibitors of Carbon Steel (CS) in 1 M H 2 SO 4 using electrochemical impedance spectroscopy (EIS) techniques, potentiodynamic polarization and weight loss measurements. The effect of temperature on the corrosion behavior of CS was studied in the range of 20-40°C. The experimental results show that EAE and BE are good corrosion inhibitors and the protection efficiency increased with increasing concentration of the extracts, but decrease with rise in temperature. The EAE and BE act as a mixed types inhibitors. The adsorption of extracts on CS surface follow Langmuir isotherm. The apparent energies, enthalpies and entropies of the dissolution process were discussed.