Milk not only contains many nutritional materials such as proteins, enzymes, carbohydrate, lipids, minerals and vitamins, but also exerts biological functions against microbial infections. Milk proteins that possess protective mechanism against infectious diseases are lactoferrin, lacto-peroxidase, lysozyme, and secretary immuno-globulins. These proteins are found not only milk, but also in other secretary fluids such as tears and saliva. These antimicrobial proteins act in cooperative manner in milk and in other fields. Lactoferrin is a member of the transferrin of iron-binding protein. Lactoferrin shows many kinds of biological functions in vitro and in vivo, including antimicrobial, antiviral, and antiparasite activity. Lactoperoxidase is an enzyme and its enzymatic product is effective for growth inhibition of microorganisms. Lactoperoxidase converts thiocyanate ion (SCN^-) to hypothiocyanite (OSCN^-) in H₂O₂-depending reaction, a potent bacteriostatic or bactericidal substance. Both lactoferrin and lactoperoxidase are expected to have antimicobial functions against infectious disease on hosts. Toxoplasma gondii is an obligatory intracellular parasitic protozoan transmitted via the ingestion of raw, infected meat. This review describes the effect of lactoferrin and lactoperoxidase to Toxoplasma gondii and its functions of these proteins against parasite.