<p>Inorganic elements in trace and ultra-trace quantities play a vital role in sustaining the life process at the molecular level. Some essential trace elements may become toxic and thereby raise concern if their potential uptake is excessive in human biochemistry. The toxicity mainly arises due to undesirable coordination with the metalloenzymes and metalloproteins. It is, therefore, mandatory to comprehend thoroughly those conditions and mechanisms, such as the concentrations and oxidation states, under which the elements become harmful and bio-toxic. To fundamentally sustain life, it is essential to understand the various polluting sources, leaching processes, chemical transformations, and deposition mechanisms that impact the ecosystem. Heavy metals can infiltrate the human body through ingestion of food, water, air, or through the skin. The discovery of Minamata disease still stands as the most prominent example that illustrates the complex ecological pathway of heavy metals. Toxicity of heavy metals in the soft tissues of animals or humans occurs through their unmetabolized deposition. This toxicity can lead to interference with metabolic processes, deactivation of enzymes, weakening of the antioxidant defence, oxidative stress, destruction of proteins and lipids and damage to the functioning of the kidney, brain, liver, blood composition and other important organs. Long-term exposure to the heavy metals causes several neurological diseases like Parkinson’s, Alzheimer’s and also multiple sclerosis, dystrophy and even defects in DNA lead to cancer. In order to detoxify these toxic metals from the living system, chelation therapy is required, which utilizes the administration of some suitable chelating agents to remove the toxic metal from the living body. This review discusses in detail the mechanism of metal toxicity, toxic activity in humans and detoxification of some toxic metals like arsenic, mercury, cadmium, lead, chromium and nickel.</p>