The snag caused by corrosion is one of the major problems faced by every country. In the present scenario, a study on the corrosion protection of metals occupies a distinctive position in the field of material science. Hence the investigation on inhibition effects of few drug molecules and a plant extract on mild steel and aluminium alloy 6061 have been undertaken. By considering the environmental issues and the non - toxic nature of inhibitors, drugs molecules such as Rabeprazole sulfide, Colchicine, Lumefantrine and Doxycycline hydrochloride along with a leaf extract of Acalypha torta plant selected for the study, showed remarkable corrosion inhibition efficiency. The results of the present investigation will help in handling corrosion problems and serve as references in similar situations. The mechanism and methodology developed in this work would provide an additional knowledge to corrosion science particularly in the area of acid corrosion and inhibition. This will help in tackling corrosion problems and serve as references.