I had an email exchange with a producer/seller of colloidal silver and this was my last email to them. His lies are in blue.

1) you wrote: “First off, you should understand that ppm is referring to the ratio of one thing to another. In this case, silver to water. You could have one lump of silver the size of a BB at the bottom of a jar of water and still have 40 ppm. “
That is completely wrong as is explained in the following quote:

from  http://www.nesc.wvu.edu/ndwc/articles/ot/fa04/q&a.pdf
This is an abbreviation for "parts per million" and it also can be expressed as milligrams per liter (mg/L). This measurement is the mass of a chemical or contaminate per unit volume of water. Seeing ppm or mg/L on a lab report means the same thing.

2) you wrote: “As far as silver levels in the hair, I am aware of absolutely no research that has established what it should or shouldn't be, so declaring safe or unsafe levels is totally subjective and unsubstantiated by any science.”
That is completely wrong because for decades the hair mineral analysis labs have known what is an acceptable level of silver and what is a toxic level. I provide the following links:

silver listed as a toxic element (when in excess):
http://www.safelabs.com.au/hair_mineral_testing.php

from  http://www.ncbi.nlm.nih.gov/pubmed/21286697
It was found that 34% of the population wearing silver jewelry had higher Ag [silver] content in hair than the upper value of the reference range (0.567 mg/kg) determined for subjects who did not wear jewelry. 

test for silver:
https://www.doctorsdata.com/hair-elements/

3) When colloidal silver sellers talk about the topic of possible silver toxicity they always wind up talking about argyria (blue skin) which is a very excessive condition way past normal low levels of toxicity which can be exposed with hair mineral analysis.

4) Sellers often become victims of their own promotional flap. I advise you and all your family to get your hair analyzed right away since you all have been drinking it copiously for 16 years. And then email me the results. (Not receiving anything will speak volumes.)

---end of email---

This is from the great website http://www.healthy-again.net/silver.htm
"When the human immune and detoxification system encounters a foreign, non-metabolic metal such as silver, it goes into overdrive in its attempt to detoxify and remove it, as described above. Glutathione, the primary detoxifying antioxidant, is utilized in this process. If the person has a chronic illness such as hepatitis C, the glutathione that had been utilized in detoxifying free radical toxins is now siphoned off into silver detoxification. The result could be a sudden progression of the disease, the exact opposite of what the silver proponents claim. This actually happened to one of my clients: he took colloidal silver and his ALT and AST counts suddenly increased, indicating disease progression."
(Levels of ALT may be markedly elevated as a result of exposure to drugs or other substances that are toxic to the liver. source)

The same guy wrote that colloidal silver does not kill the good intestinal bacteria and yet he holds to the scientific fact that colloidal silver kills all bacteria it encounters. He wants to change the facts to benefit him and his sales of colloidal silver. If colloidal silver kills intestinal bacteria then it is just as disruptive to good digestion as antibiotics are and should not be used unless truly necessary. And if ingested then dosages of acidophilus should be taken for a week afterwards.