Present study investigate the corrosion inhibition action of green non‐steroidal anti‐inflammatory drugs (NSAIDs) on mild steel (MS) in 1 M HCl by Gravimetric method, Electrochemical Impedance Spectroscopy and Potentiodynamic Tafel polarization at 303.15 K. Changes occurring in the impedance parameters (Rct and Cdl) give clear indication of drug adsorption on the metal surface. Polarization study inferred these drugs to act as a mixed inhibitor. Experimental results inferred a rise in inhibition efficiency with increasing drug concentration. i. e. 90%, 71% and 85% for Aspirin (∼0.3 mM), Diclofenac (∼0.1 mM) and Ibuprofen (∼0.7 mM) respectively. The formation of the Fe‐inhibitor complex and the corrosion inhibition mechanism was inferred by spectral study. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) gave evidences of the surface topography and proved that the metal surface resist corrosion in presence of inhibitor than in its absence. The degree of hydrophobicity induced due to drug adsorption as obtained by contact angle (CA) is in good agreement with the microscopic results which inferred NSAIDs to act as an effective inhibitor in acidic corrodent. Thermodynamic study confirmed the adsorption process to be spontaneous i. e., ΔG̊ads lies between −17.0 to −20.0 kJ mol−1 which obeyed the Langmuir isotherm. A successive correlation of NSAIDs with their calculated molecular orbital energy levels is well explained using simulation by Density Functional Theory.

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