Radiation therapy and/or chemotherapy generate free radicals that eradicate cancer cells. Recent studies show that supplementing with high doses of antioxidants could neutralize these free radicals, thereby reducing the efficacy of treatments. We strongly advise against taking such supplements during treatment. However, food does not contain enough antioxidants to interfere with chemotherapy. In addition, plant-based foods are not just a source of antioxidants. They are also rich in a variety of anticancer molecules that could interfere with processes that trigger the onset of cancer.