Lactoferrin is a protein present in many fluids of the human organism and in the secondary granules of polymorphonuclear cells (PMN). In the blood stream lactoferrin favours the segregation of PMN by mediating and amplifying the immune response, and realizes a negative feedback control on the Colony Forming Unit Granulocyte/Macrophage (CFU-GM) proliferation. At intestinal level it promotes iron absorption and prevents bacterial overgrowth. The antibacterial effect of lactoferrin is used clinically to prevent bacterial infections in neutropenic patients submitted to chemotherapy for leukemic diseases type M1, M2, M4 and M5, according to FAB criteria. In patients affected by chronic pancreatitis the lactoferrin concentration, in duodenal juice, is found to be significantly higher than in normal subjects. This finding suggests a pathogenetic role of the protein in chronic pancreatitis.