Silver compounds may be absorbed through inhalation, but there are no quantitative human data on the extent of this phenomenon. Silver salts may be absorbed by up to 10%–20% after ingestion. After ingestion in humans, the highest concentrations of silver are usually found in the liver and spleen, but also to some extent in the muscles, skin, and brain. Silver may also be absorbed through dermal exposure, especially via wound care. The biological half-time for silver ranges from a few days for animals up to approximately 50days for the human liver; it is possible that skin deposits have an even longer half-time, but there are no quantitative data on this for humans. Silver binds to high molecular weight proteins and metallothionein in tissue cytosol fractions. Excretion of silver from the body is primarily biliary. Silver nanoparticles have been shown to be absorbed by both inhalation and oral routes, and only to a minor extent via the dermal route, resulting in deposition in various organ systems. Monitoring of exposure is possible by determinations of levels in whole blood. High-dose repeated exposure of animals to silver and silver compounds may produce anemia, cardiac enlargement, growth retardation, and degenerative changes in the liver. Water-soluble silver compounds such as silver nitrate have a local corrosive effect and may cause fatal poisoning in humans if injected or infused into the uterus. Chronic exposure of humans leads to argyria, a clinical entity characterized by gray-blue pigmentation of the skin and other body viscera. Similar changes in the eye after local treatment with eye drops containing silver compounds are named argyrosis. Allergic contact dermatitis to silver is rare. Genotoxic effects, in terms of direct DNA strand breaks via oxidative stress, have been reported in vitro. Tests indicating genotoxicity (Comet assay) and oxidative stress were positive in one study on silver-workers.