If a copper article is used it can leave black marks on skin. Also, copper jewelry should be actual copper, not copper plated. Copper toxicity Toxicity can reduce the stability of vitamins A and C and can reduce the ability of enzymes in the human body. Wilson's disease is an inherited tendency to accumulate copper in the liver and brain. Copper sulfate has been used as a lethal poison with a dose of 7.5g resulting in death.
Copper poisoning can also occur due to the use of copper vessels for cooking or serving vessels.
Sauerkraut, apples, cider, beer, wines and vinegar also dissolve the metal. The copper content of the food rises as the food becomes more acidic or when the water temperature increases. Copper can also come from pollutants in the water supply. About 7.6 grams of copper sulfate is a lethal dose for human adults. Paracelsius in Greece used copper for tuberculosis, and it has been used in the treatment of cholera and typhoid.