Carbon steel, the most widely used engineering material, despite its relatively limited corrosion resistance used in large tonnages in marine applications, nuclear powered transportation, chemical processing , petroleum production and refining, pipelines, mining, construction and metal-processing equipment. The main objective of the present work involved the study of the inhibiting properties of natural product as Spearmint plant extract as a safety and an environmentally friendly corrosion inhibitor for low carbon steel in (3.5% NaCl) solution. Results showed when the immersion model in (3.5% NaCl) solution that contains the inhibitor with concentration of (15% in volume), it s getting a decrease in lost weight , indicating a layer of adequate oxide on the surface of the steel, indicating that the amount of loss weight decrease with increasing concentration of inhibitor and this shows the damper on his ability to form a protective layer .