This study aimed to compare the action of a drug (ezetimibe) and a functional food containing plant sterol esters on oxidative stress biomarkers. In this double-blind study, 37 type 2 diabetic patients on statin treatment were randomly assigned to receive ezetimibe 10.0 mg/day or to consume a chocolate containing 2.1 g of plant sterol esters for 6 weeks. It was observed that ezetimibe promoted an increase of superoxide dismutase and glutathione reductase activities, while plant sterols did not change these biomarkers. Among individuals who showed the greatest LDL-C and oxLDL-C reduction, the oxLDL-C reduction observed in individuals under plant sterol treatment (−20.0%) did not differ from the values found in individuals treated with ezetimibe (−21.1%). In addition, 16 patients on plant sterol treatment reached the optimal therapeutic goal for LDL-C (