The current standard adjuvant chemotherapy for suitable patients with stage III colon cancer is the combination of oxaliplatin and 5-fluorouracil plus folinic acid (5-FU/LV). However, until recently and for many years prior to this, the accepted standard adjuvant chemotherapy was 6–8 months of bolus 5-FU/LV. However, bolus treatment was associated with significant toxicity, namely stomatitis, diarrhea and neutropenia, in addition to multiple hospital visits for drug administration for patients. The X-ACT trial (Xeloda in Adjuvant Colon Cancer Therapy) compared traditional bolus 5-FU/LV (as per the Mayo Clinic regimen) with capecitabine, in the adjuvant treatment of 1987 stage III colon cancer patients. The main safety, efficacy and pharmacoeconomic results have all been published, and the updated 5-year efficacy results have also recently been presented. This trial demonstrated that capecitabine was at least as effective as bolus 5-FU/LV in terms of disease-free and overall survival, with trends towards superiority for both. Moreover, there was much less toxicity associated with capecitabine, apart from hand–foot syndrome which was significantly more prevalent. On the basis of the X-ACT trial, capecitabine was approved by the US FDA, the National Institute for Clinical Excellence and the Scottish Medicines Consortium as monotherapy for the adjuvant treatment of stage III colon cancer.