Colorectal cancer continues to be one of the most frequently diagnosed malignancies worldwide. While a curative treatment remains surgical excision, chemotherapy is an important treatment in later stages, perhaps due its elimination of micrometastases that are not readily visible during surgery (not to mention its effect on larger metastases in stage IV disease). Chemotherapeutic drugs currently approved for the use in adjuvant treatment of stage III and some cases of stage II colorectal cancer are the fluoropyrimidines 5-fluorouracil and capecitabine (with or without the addition of folinic acid, which augments their action) and the platinum analog oxaliplatin. These drugs are used in several combination therapies that increase the disease-free survival and overall survival of patients. This paper reviews the pharmacological aspects of these three chemotherapeutic agents and of folinic acid, which is a part of most regimens.