Copper is an essential trace element, but excessive amounts can be toxic. Wilson disease (WD) is a genetic disorder causing copper accumulation in the liver and brain, leading to severe health issues. Copper toxicity can result from accidental ingestion, poisoning, or chronic overload. The article reviews copper's role in cellular functions, its transport mechanisms, and the toxic effects of excess copper on cells, particularly in the liver and brain. Copper is transported via specialized proteins, and its toxicity can lead to oxidative stress, mitochondrial damage, and protein dysfunction. In WD, copper accumulation causes liver dysfunction and neurological symptoms. The article also discusses the mechanisms of copper toxicity, including oxidative stress, cuproptosis, protein toxicity, and interference with signaling pathways. Chronic copper overload can lead to cancer and other diseases. Treatment options for acute and chronic copper toxicity are discussed, with a focus on Wilson disease, which is caused by mutations in the ATP7B gene. The article highlights the importance of copper homeostasis and the need for effective therapies to manage copper-related diseases.Copper is an essential trace element, but excessive amounts can be toxic. Wilson disease (WD) is a genetic disorder causing copper accumulation in the liver and brain, leading to severe health issues. Copper toxicity can result from accidental ingestion, poisoning, or chronic overload. The article reviews copper's role in cellular functions, its transport mechanisms, and the toxic effects of excess copper on cells, particularly in the liver and brain. Copper is transported via specialized proteins, and its toxicity can lead to oxidative stress, mitochondrial damage, and protein dysfunction. In WD, copper accumulation causes liver dysfunction and neurological symptoms. The article also discusses the mechanisms of copper toxicity, including oxidative stress, cuproptosis, protein toxicity, and interference with signaling pathways. Chronic copper overload can lead to cancer and other diseases. Treatment options for acute and chronic copper toxicity are discussed, with a focus on Wilson disease, which is caused by mutations in the ATP7B gene. The article highlights the importance of copper homeostasis and the need for effective therapies to manage copper-related diseases.