Leucorin 15mg tablet contains Leucovorin Calcium (folinic acid), a biologically active derivative of folic acid used as a “leucovorin rescue” agent. It works by providing an active form of folate that bypasses dihydrofolate reductase (DHFR) inhibition, protecting healthy cells from the toxicity of methotrexate . Leucorin Tablet is used to prevent the harmful effects of methotrexate (anticancer medicine). It is also used in the treatment of methotrexate overdose.