evidence: The U.S. Food and Drug Administration (FDA) has warned that colloidal silver isn’t safe or effective for treating any disease or condition. Additionally, the FDA and the Federal Trade Commission have taken action against a number of companies for making misleading claims about colloidal silver products. [...] Colloidal silver was used to treat infections and wounds before antibiotics became available. [...] A few studies have evaluated the effectiveness of colloidal silver nasal spray to treat chronic sinus infections, but they did not demonstrate meaningful improvements.