LEVOLEUCOVORIN prevents side effects from certain medications, such as methotrexate. It works by increasing folate levels. This helps protect healthy cells in your body. It may also be used with fluorouracil, a type of chemotherapy, to treat colorectal cancer. It works by increasing the effects of fluorouracil in the body. With the Patient Assistance Program from Novartis, you can receive your medication at no cost.