Lactoferrin is an iron-binding protein from the transferrin family and was first isolated from milk. Lactoferrin is produced by polymorph nuclear leukocytes and epithelial cells of many mammalian species and is present in such mucosal secretions as tears, saliva, seminal and vaginal fluids as well as in several organs and blood. Many biological functions of lactoferrin have been identified: iron absorption, bacteriostatic, bactericidal, fungicidal, antiviral, antiparasitic and antitumour activities. It is also well known for its immunomodulatory and antiinflammatory properties. Additionally, lactoferrin is thought to possess protease, ribonuclease, procoagulant and transcription factor activities. Nowadays bovine lactoferrin is isolated and purified on an industrial scale and used for food preservation and production of infant formulas, yogurt, skim milk, chewing gum, cosmetic formulas, nutritional supplements and therapeutic supplements for pets. The use of lactoferrin as an immunostimulator is a promising area especially in the case of patients with immunosupression.