Attention Deficit Hyperactivity Disorder (ADHD) is highly prevalent neurobehavioral disorder with genetic, environmental and biologie etiologies that persist to adolescence and adulthood. Major etiologic contributors inc-lude adverse responses to food additives, sensitivities to environmental chemicals, molds and fungi and also exposure to the neurodevelopmental toxins such as heavy metals and the other toxic pollutants. Free radicals play an important role in the pathogenesis of many pediatrie diseases, including also ADHD. Several studies háve shown that metals like copper, iron, cadmium, chromium, mercury, lead participate in the produce of free radicals resulting in DNA damage, lipid peroxidation, depletion of protein sulphydryls and the other effeets. It is also known that some essential elements such as zinc and selenium possess the ability to act as antioxidants and reduce oxidative stress.

        Key words: Attention Deficit Hyperactivity Disorder, heavy metals, free radicals, oxidative stress