Copper is a biogenic metal having multiple functions in basic processes in organisms and it is common in all kingdoms of life. Limited intake of copper is a problem; however, doses of copper exceeding the recommended alimentary source are problematic as well and toxicity is soon manifested. Impact of copper nanoparticles on human health is another serious issue taken into consideration in this review. Regarding to copper toxicity, neurodegenerative disorders including Alzheimer and Parkinson diseases are suspected to be linked to copper toxicity or copper can contribute to their progression. Wilson and Menke diseases are also described as examples of copper intolerance. This paper is focused on the description, literature survey and discussion of the current knowledge about copper and copper nanoparticles toxicity and their involvement in various pathological processes (Tab. 6, Fig. 2, Ref. 171).