The corrosion inhibition of mild steel in 1M Sulphuric acid using amoxicillin as inhibitor has been investigated by weight loss, Potentiodynamic polarization, electrochemical impedance spectroscopy, Hydrogen permeation and diffuse reflectance spectroscopic measurements. All these techniques reveal that inhibition efficiency increases with an increase in the concentration of inhibitor. Scanning electron microscopy [SEM] was portrayed for uninhibited and inhibited mild steel surfaces to ascertain the adsorption of inhibitor on the metal. Potentiodyanamic polarization studies indicated that inhibitor act as mixed type. Diffuse reflectance spectroscopy and quantum mechanical calculations substantiated the mere adsorption of inhibitor on the mild steel surface which is responsible for corrosion inhibition of steel in 1M Sulphuric acid. The adsorption of the compounds on mild steel surface obeys Langmuir adsorption isotherm.