The endogenous (natural) 1-2 nm metal particles play significant roles in human health and disease. Each milliliter of human blood contained approximately 7 x10^13 metal nanoparticle. They are 1- to 2-nm metallic nanoclusters containing 40–300 atoms. They are shown to kill cancer cells, enhance the sense of smell, control blood cells vesiculation in heat stress, and regulate maturation of stem cells in the newly discovered primo vascular system. Attached please find a few articles describing the a positive role of nanoparticles in human and animal physiology.