Résumé : Leucovorin Sodium (LV/Na) has a high solubility, and is stable when given with continuous infusion of 5-FU. It could maintain significant plasma concentration of 5, 10-meTHF during the whole 5-FU perfusion with the potential of increasing 5-FU cytotoxicity. We conducted a randomized phase II clinical trial on leucovorin calcium (LV/Ca) and LV/Na in metastatic colorectal cancer patients (mCRC). Main objectives were to assess efficacy and safety.