Chemical and electrochemical techniques were used to test the expired No Plac medication as a corrosion inhibitor for carbon steel in 1.0 M HCl. The results showed that No Plac may play an essential function as a corrosion inhibitor for carbon steel. Due to the adsorption of drug molecules on the carbon surface, the protection efficiency increases with increasing drug concentrations. It was also discovered that the adsorption followed the Frumkin isotherm. The polarization results revealed that the expired medication inhibits both cathodic and anodic processes, indicating that it is a mixed inhibitor. The expired medication enhances polarization resistance by adsorbing on the metal/electrolyte contact, according to EIS test. Finally, the calculated thermal parameters showed the spontaneous and physical adsorption of the drug molecules on the metal surface, as well as the excellent role of the drug at different temperatures.