Patients are not at risk of dying from a tumor that has been removed; they are at risk of dying from residual microscopic disease not removed at the time of operation. Thus, the goal of an adjuvant treatment, be it chemotherapy, radiation therapy, immunotherapy, or dietary and lifestyle manipulations, is to eradicate any residual, albeit microscopic, metastatic disease that might remain. Stage I disease carries an excellent prognosis, and at present there are no compelling data to support adjuvant chemotherapy for patients with this early stage. Stage II colon cancer also has a good prognosis after operation alone and represents the most complicated and contentious area in decisions regarding the use of adjuvant chemotherapy. Stage III colorectal cancer (TanyN 1–2M 0) represents a group at a higher risk of recurrence, and this population is routinely given adjuvant chemotherapy in the absence of a medical or psychiatric contraindication.