The Antibacterial Effects of Silver and it's compounds
In General

Silver has germicidal effects and kills many lower organisms effectively without harm to higher animals.

Silver is capable of rendering stored drinking water potable for a long period of time (several months). Water tanks on ships and airplanes are often "silvered".

Disposal of even small quantities of Silver Nitrate connected to a septic tank is guaranteed to destroy the septic bacteria and require pumping out, flushing and seeding with fresh bacteria.

Silver Nitrate has antiseptic properties. A very dilute solution is sometimes dropped into newborn babies' eyes at birth to prevent contraction of gonorrhoea or chlamydia from the mother.

Fused Silver Nitrate, molded into sticks, was traditionally called lunar caustic. It is used as a cauterizing agent. Silver Nitrate is melted at 212°C ( 413°F ) and poured into a mold of the desired shape.

Silver Chloride is used as an Antibacterial agent for concrete ( 1 Lb Silver Chloride per cubic yard of Concrete (4,050 lbs) ).

Silver Chloride is used to help prevent bacteria from growing on Glass (when melted into the glass).

Silver Carbonate is used as an Antibacterial agent for concrete ( 1 Lb Silver Carbonate per cubic yard of Concrete (4,050 lbs) ).

Silver Carbonate is used as a biocide against bacteria, yeasts and molds in some Paints and Resins.

In Today's Marketplace

Samsung has introduced washing machines that inject silver ions into the wash and rinse cycles to kill 99.9% of odor causing bacteria. Silver atoms, electrolytically stripped of an electron, are injected during the wash and rinse cycles, allowing over 100 quadrillion silver ions to penetrate deep into the fabric to sanitize clothing without the need for hot water or bleach. These machines can wash about 3,100 loads using 1 Troy Ounce (31.1 grams) of Silver metal. [more]

Kohler has introduced a line of toilet seats that include an antimicrobial agent formed into the plastic which inhibits the growth of odor causing bacteria, mold and mildew. [more]

American Standard StayClean™ whirlpool systems have plastic pipes manufactured with Antimicrobial Alphasan® which are blue in color. This revolutionary material uses silver's natural antimicrobial characteristics to help keep the whirlpool free of 99.9% of microbes, mold and mildew.

NanoHorizons, Inc. SmartSilver™ are nanoscale silver additives for urethane, nylon and cotton. These permanent anti-odor/antimicrobial additives are added to the fibers during manufacturing. [more]

Electrical Ionization units impregnate water with silver and copper ions. These sanitize pools, spas and fountains without the harsh effects of chlorine. [more]

AgION® Silver based antimicrobial protects Logitech wireless keyboard/mouse against a broad spectrum of bacteria. [more]

Sherwin-Williams® Silver based antimicrobial will provide FasTop™ Flooring Systems with continuous protection against a broad spectrum of microbes. [more]

Ice-O-Matic® Uses Silver based antimicrobial protection for the life of their ice cube machines to prevent bacteria, slime and fungus growth. [more]

FoodTouch® silver based food packaging liners preserve food quality. Superior to parchment, wax or butcher paper. [more]

In Medicine

Silver or silver compounds are used externally in wound and burns treatment.

Curad® Natural Silver Antimicrobial bandages. Laboratory testing showed that silver reduced bacterial growth like Staph. aureaus, E. coli, E. hirae and Pseudomonas aeruginosa (a powerful germ that does not respond to many antibacterials) in the dressing for 24 hours. [more]

Elastoplast® Silver Healing™ bandages. The pads in these bandages contain silver ions. These ions kill over 150 different bacteria, fungi, yeast and other harmful germs. [more]

Silver Sulfadiazine is an antibacterial and antifungal agent. It is used as a topical cream to prevent and treat skin infections on areas of burned skin. The U.S. patent for Silver Sulfadiazine issued in September 1973. [more]

Silver Chloride has the ability to eliminate or flush out mercury from the body.

Silver Chloride is used as a thin coating on the surface of Medical Electrodes for EKG machines. (Placed against the skin).

Silver Chloride is used as an anti microbial agent in some infection resistant surgical fabric materials.

Silver Chloride is used to help prevent bacteria from growing on Latex (mixed into the Latex before it is formed).

Silver Carbonate is used as a biocide against bacteria, yeasts and molds in some Cosmetics.

Silver Carbonate is used in some topical antibiotic creams ( about 1% Silver Carbonate ).

Silver Carbonate is used in some tooth surface treatments to prevent cavities.

In History
  • Hippocrates, the father of modern medicine, wrote that silver had beneficial healing and anti-disease properties.
  • The Phoenicians used to store water, wine, and vinegar in silver bottles to prevent spoiling.
  • Prior to antibiotics, Colloidal Silver was used widely in hospitals as a bactericide.
  • In the early 1800s, doctors used silver sutures in surgical wounds with very successful results.
  • Pioneers of the American West found that if they placed silver or copper coins in their casks of drinking water, it kept the water safe from bacteria, algae, etc.
  • In the early 1900s people would put silver dollars in milk bottles to prolong the milk's freshness.
  • Silver compounds were used successfully to prevent infection in World War I (before antibiotics).
  • Silver leaf was used to combat infection in wounds sustained by troops during World War I.
  • By 1940 there were approximately four dozen different silver compounds on the market being used to treat every known infectious disease.
  • Settlers in the Australian outback suspend silverware in their water tanks to retard spoilage.
  • The widespread use of silver went out of fashion with the development of modern antibiotics. However, recently there has been renewed interest in silver as a broad spectrum antimicrobial. In particular, it is being used with alginate, a naturally occurring biopolymer derived from seaweed, in a range of silver alginate products designed to prevent infections as part of wound management procedures, particularly applicable to burn victims.
Health precautions

Silver plays no known natural biological role in humans, and possible health effects of silver are a subject of dispute. Silver itself is not toxic but most silver salts are, and some may be carcinogenic.

Silver and compounds containing silver (like colloidal silver) can be absorbed into the circulatory system and become deposited in various body tissues leading to a condition called argyria which results in a blue-grayish pigmentation of the skin, eyes, and mucous membranes. Although this condition does not harm a person's health, it is disfiguring and usually permanent. Argyria is rare and mild forms are sometimes mistaken for cyanosis.

Silver Ions and silver compounds show a toxic effect on some bacteria, viruses, algae and fungi typical for heavy metals like lead or mercury, but without the high toxicity to humans that is normally associated with them. Its germicidal effects kills many microbial organisms in vitro (i.e. in a test tube or a petri dish). The exact process by which this is done is still not well understood, although several different theories exist. One of these is a process generally known for heavy metals called the oligodynamic effect, which goes a long way explaining the effect on microbial lifeforms but does not explain certain antiviral functions.

Alternative Medicine

Today, various kinds of silver compounds, or devices to make solutions or colloids containing silver, are sold as remedies for a wide variety of diseases. Although mostly harmless, some people using these home-made solutions use far too much and develop argyria over a period of months or years, and several have been documented in the last few years in the medical literature, including one possible case of coma associated with a high intake of silver (see medical references). It is strongly advised to notify a doctor when taking silver as a form of self-medication.

In Food

In India, foods can be found decorated with a thin layer of silver, known as Varak. Silver as a food additive is given the E number E174 and classed as a food coloring. It is used solely for external decoration, such as on chocolate confectionery, in the covering of dragées and the decoration of sugar-coated flour confectionery. In Australia, it is banned as a food additive.

Superstition

Because of the mysticism surrounding silver's lunar associations, as well as the aesthetic qualities of the white, reflective metal that cause it to be associated with purity, silver in European Folklore has long been traditionally believed to be an antidote to various maladies and fictional monsters. Notably, silver was believed to be a repellent against vampires (this primarily originates from its holy connotations; also, mirrors were originally polished silver, and as such, vampires allegedly cannot be seen in them because they are wicked) and it was believed that a werewolf, in his bestial form, could only be killed by a weapon or bullet made of silver, and was equally effective against vampires, as described in Eastern European folklore. This has given rise to the term "silver bullet," which is used to describe things designed to cure or fix a wide array of maladies.

The Ogligodynamic Effect

Discovered in 1893 by the Swiss KW Nägeli as a toxic effect of metal-ions on living cells, algae, moulds, spores, fungi, virus, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations. This antimicrobial effect is shown by ions of: mercury, silver, copper, iron, lead, zinc, bismuth, gold, aluminum and other metals.

Especially heavy metals show this effect. The exact mechanism of action is still unknown. Data from silver suggest that these ions denature proteins (enzymes) of the target cell or organism by binding to reactive groups resulting in their precipitation and inactivation. Silver inactivates enzymes by reacting with the sulfhydryl groups to form silver sulfides. Silver also reacts with the amino-, carboxyl-, phosphate-, and imidazole-groups and diminish the activities of lactate dehydrogenase and glutathione peroxidase. Bacteria (gram+ and gram-) are in general affected by the oligodynamic effect, but they can develop a heavy-metal resistance, or in the case of silver a silver-resistance. Virus in general are not very sensitive. The toxic effect is fully developed often only after a long time (many hours).

Further Reading:
Technical Literature Sources Which Demonstrate the Antimicrobial Properties of Silver