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Am Fam Physician. 2004;70(6):1174

Consumer Advisory on Colloidal Silver Products

The National Center for Complementary and Alternative Medicine (NCCAM) has issued a consumer advisory of colloidal silver products. The advisory is available online at

Colloidal silver products contain tiny silver particles suspended in liquid. They are marketed as dietary supplements and claim to benefit the immune system; kill disease-causing agents such as bacteria, viruses, and fungi; offer an alternative to prescription antibiotics; and treat diseases such as cancer, human immunodeficiency virus, acquired immunodeficiency syndrome, tuberculosis, syphilis, scarlet fever, shingles, herpes, pneumonia, and prostatitis. These claims have not been proven.

According to the NCCAM, over-the-counter colloidal silver products are not considered by the U.S. Food and Drug Administration (FDA) to be generally recognized as safe and effective for diseases and conditions. The FDA has taken action against a number of companies for making drug-like claims about these products.

Colloidal silver can cause serious side effects. One is argyria, a bluish-gray discoloration of the body. Argyria is not treatable or reversible. Other side effects include neurologic problems (e.g., seizures), kidney damage, stomach distress, headaches, fatigue, and skin irritation. In addition, colloidal silver may interfere with the body’s absorption of prescription medications, including penicillamine, quinolones, tetracyclines, and thyroxine.

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