evidence: Colloidal silver can kill certain germs by destroying proteins, which is why it was previously used in wound dressings. But silver has no known function in the body and is not an essential mineral. Taking silver by mouth can cause the skin to turn a permanent bluish color. It can also cause brain function problems. Colloidal silver has been used for infections, hay fever, skin conditions, and many other conditions, but there is no good scientific evidence to support any of its uses. There is also no good evidence to support using colloidal silver for COVID-19. It can be unsafe when taken by mouth, applied to the skin, or inhaled. [...] Possibly Ineffective for - Swelling (inflammation) of the nasal cavity and sinuses (rhinosinusitis). Using a nasal spray containing colloidal silver does not work any better than saline nasal spray for reducing symptoms of sinusitis.