The ubiquitous presence of lactoferrin(LF) receptor in human as reported by the research group of Prof. Bo Lonnerdal, Univ. California (Suzuki, Y. A.,2001) encouraged us to search for the unknown physiological roles of Lf. Under the collaboration with Prof. Etsumori Harada, Tottori Univ., and his research group, we have found two novel biological activities of LF as the control of the lipid metabolism and the effect on the central nervous system. Relating to the lipid metabolism, LF could, in animal experiments, reduce triglyceride and total cholesterol both in blood and liver (Takeuchi, T et αl., 2003). LF increased plasms HDL-C and lowered LDL-C. In the central nervous system, LF showed anti-nociceptive activity mediated by ${mu}$-opioid receptor in the rat spinal cord (Hayashida, K. et al., 2003). LF enhanced analgesic action of morphine synergistically via nitric oxide synthesis (Hayashida, K., et al., 2003) LF showed opioid-mediated suppressive effect on distress induced by maternal separation in rat pups (Takeuchi, T., et al., 2003).