This article provides a comprehensive analysis of the environmental and clinical impacts of copper, iron, cadmium, and arsenic on human health, with a focus on liver injury. The authors highlight that these metals, while essential in trace amounts, can pose significant health risks when present in excess. Copper and iron, when maintained within physiological ranges, are crucial for various metabolic processes and are essential for human health. However, genetic disorders like Wilson disease and hemochromatosis can lead to excessive copper accumulation, causing liver damage. Cadmium and arsenic, on the other hand, lack beneficial effects and are considered harmful due to their long-term deposition in the liver and other organs, leading to increased disability-adjusted life years and mortality rates from cancer and non-cancer diseases. The article discusses the molecular mechanisms behind the toxic effects of these metals, including the Haber Weiss and Fenton reactions involving reactive oxygen species. It also addresses the challenges in diagnosing and managing liver injury caused by heavy metals, emphasizing the need for careful clinical evaluation and exclusion of alternative causes. The authors conclude that while copper and iron are generally beneficial, cadmium and arsenic pose significant health risks, and efforts should focus on reducing industrial emissions of these hazardous metals.This article provides a comprehensive analysis of the environmental and clinical impacts of copper, iron, cadmium, and arsenic on human health, with a focus on liver injury. The authors highlight that these metals, while essential in trace amounts, can pose significant health risks when present in excess. Copper and iron, when maintained within physiological ranges, are crucial for various metabolic processes and are essential for human health. However, genetic disorders like Wilson disease and hemochromatosis can lead to excessive copper accumulation, causing liver damage. Cadmium and arsenic, on the other hand, lack beneficial effects and are considered harmful due to their long-term deposition in the liver and other organs, leading to increased disability-adjusted life years and mortality rates from cancer and non-cancer diseases. The article discusses the molecular mechanisms behind the toxic effects of these metals, including the Haber Weiss and Fenton reactions involving reactive oxygen species. It also addresses the challenges in diagnosing and managing liver injury caused by heavy metals, emphasizing the need for careful clinical evaluation and exclusion of alternative causes. The authors conclude that while copper and iron are generally beneficial, cadmium and arsenic pose significant health risks, and efforts should focus on reducing industrial emissions of these hazardous metals.