The objective of this comprehensive review is to update the impact of Sodium Fluoride on human system and other life on the earth. Sodium Fluoride is a source of Fluoride ion used in miscellaneous applications includes health, insecticidal and metallurgical. Fluoride is often referred as "double edged sword" because in small doses it acts as an essential trace element and on excessive exposure it causes harmful effects.It is a known fact that Fluoride prevents dental caries through dual-mode of action; inhibits demineralization and enhances the remineralisation of dental hard tissues.The ionic Fluoride in saliva, enamel and dentin shifts the equilibrium of demineralizationremineralisation toward remineralisation. Fluoride acts as a catalyst for the uptake of calcium and phosphate ions and results in a greater efficiency in demineralising the areas of enamel and dentin that have been affected by acidic attack. On the other hand, excess levels show negative impact on different systems in humans. When Fluoride concentration exceeds permissible levels it shows impact on plants, animals, microorganisms and different enzymes involved in metabolic processes. It affects flora growth by the inhibition of Enolase and other metabolic enzymes.Enolase plays a key role in glycolysis, an energy (ATP) synthesis source for the flora and decreases production of ATP. Improper ATP synthesis directs the impact on further molecular mechanisms leading to death of organism.The antibacterial action of Fluoride on the organism is due to acidification of bacterial cytoplasm.