In combination chemotherapy for metastatic colorectal cancer, i.v. 5-fluorouracil (5-FU) can be replaced by oral 5-FU (in the form of capecitabine or another orally available analogue) without negatively affecting overall toxicity and without remarkably reducing the efficacy of treatment in terms of response rate or overall survival. Preclinical evidence of synergy has led to promising early and successfully completed studies combining capecitabine plus oxaliplatin with bevacizumab, cetuximab, and epidermal growth factor receptor tyrosine kinase inhibitors. The use of preoperative capecitabine plus radiation is achieving good rates of pathological complete response in rectal cancer. While capecitabine is generally well tolerated, its potential toxicities need careful management and may require individual dose adaption.