Jumping into the fray :) .... I decided to go do some literature searches on the MEDLINE database to see what I could find about the use of colloidal silver. The first thing I noticed is that there really is very little out there on the use of colloidal silver, and I couldn't find any papers detailing any sort of clinical research on its use. I've listed below what I did find and tried to give a brief summary of each item. Anyone living near a university, particularly one with a vet or med school, should be able to find these articles. If you can't find them, ask the library to get them on interlibrary loan (takes 1-2 weeks). I had to do that for a couple of them myself because our med school libraries didn't have a particular journal, or had cancelled a subscription. 1. Antibacterial Efficacy of a Colloidal Silver Complex, Brentano, L., Margraf, H., Monafo, W.W., and Moyer, C.A. Surgical Forum 17: 76-78, 1966. In order to determine the best agent for antibacterial use on wound dressings for burns, the authors tested silver nitrate, colloidal silver ("Collargol Rx" - no specifics given), and a mixture of silver nitrate and Collargol. They tested these three agents against three strains of bacteria, under three different growth conditions. In all cases they found that colloidal silver alone was relatively ineffective, as compared to either the silver nitrate alone, or the mixture, requiring up to a 40-fold higher concentration to attain the same effect. 2. Antimicrobial Activity and Action of Silver, Russell, A.D., and Hugo, W.B. Progress in Medicinal Chemistry 31:351-370, 1994. This is a rather long paper which goes into the historical aspects of silver use, the properties and uses of silver compounds, the mechanisms of antimicrobial action, and bacterial resistance to silver. Obviously I can't summarize the whole thing here but there are some interesting points. Pure silver is inactive, however surface-oxidized or tarnished silver has the antimicrobial effect. In general the antimicrobial action of silver is decreased in the presence of proteins, phosphates, chlorides, sulphides, and hard water. Argyria can occur as a result of prolonged silver therapy, one example being noted of a 59 year old patient undergoing silver sulfadiazine therapy for venous leg ulcers. Bacterial resistance to silver can be either acquired or innate. This paper does not focus on any one silver compound and does not mention colloidal silver much at all. It is however, a very good overview and would be interesting reading, especially for anyone with a background in chemistry or biochemistry. 3. Silver Products for Medical Indications: Risk-Benefit Analysis, Fung, M.C., and Bowen, D.L. Journal of Toxicology - Clinical Toxicology, 34(1):119-126, 1996. This paper goes somewhat into the history of silver use and its physical and chemical properties. It also mentions the dose considered as safe exposure by the EPA, called the Reference Dose (Rfd), which is an estimate of daily exposure that is not likely to be associated with deleterious effects during a person's lifetime. The Rfd for oral silver exposure is 5ug/kg/d, which translates to 350ug/d for a 70 kg adult. They have a table listing OTC as well as prescription silver products. Seven cases of argyria are noted, in which people were self-treating with various silver products. In their conclusion, they "emphasize the lack of established effectiveness and potential toxicity of these products." Based on what I've read, and what I haven't read (IOW, I haven't seen any peer-reviewed papers which say that colloidal silver is safe and effective), I won't be using it on myself or my ferrets. While certain silver compounds have been used successfully for external treatments, I can't see that it would be any more useful internally than antibiotics, which are targeted to certain bacteria, rather than having a general effect (silver cannot distinguish between good and bad bugs). Added to that the potential for toxicity, and I don't feel the risk is justified. If anyone does decide to use it, just be aware of the potential pitfalls. Silver is not a magic bullet. Karen [log in to unmask] ====================================================================== A righteous man has regard for the life of his beast, but the mercy of the wicked is cruel." (Proverbs 12:10 RSV) ====================================================================== If you love ferrets, check out: http://www.dartmouth.edu/~crassi/index.html ====================================================================== [Posted in FML issue 2587]