Metal and metal oxide nanoparticles are now commonly used in a variety of medical and pharmaceutical applications such as gold (Au), selenium (Se), silver (Ag) and copper (Cu) nanoparticles. The nanometals are characterized by ultra-small particle size and large surface area, making them of great interest in the treatment of bacterial infections. Au-NPs are used in a variety of medical applications such as gene, and drug delivery, photo-thermal, photodynamic, and radiation therapy, as well as various biological applications. Se-NPs exhibit potential therapeutics in various inflammatory disorders, such as nephropathy, arthritis, diabetes, and cancer. Se-NPs are considered as safe carriers of various drugs to the site of action with antioxidant activity, pro-oxidant effects, and anticancer effects. Ag-NPs have mainly pharmaceutical applications as used in burn cure and many other health related properties. Furthermore, Now days, Cu-NPs are used in different textile industries as well as in different drugs industries.