St. Amand, Guaifenesin, Salicylate and MCS

A correspondent reminded me of Dr. St. Amand work, and I recall some 12 years ago corresponding with a person that went into remission taking Guaifenesin, a remission that lasted for 6 months.  I decided it was time to see if the stable dysfunction microbiome hypothesis and these earlier experiences may be connected.

My Model of Multiple Chemical Sensitivity

For several years I have used a model that multiple chemical sensitivity was due to miss-identification by the body of some chemicals as signals of a biological infection (virus or bacteria). I have seen a person with MCS have a coagulation panel immediately before a MCS reaction and two weeks after show a massive jump( 6 standard deviations) in the a coagulation marker with a very short half life (thus indicating active coagulation). The MCS reaction had triggered massive active coagulation which would explain many, if not all, of the symptoms of MCS.  This was later confirm by an experiment with a MCS person with gluten sensitivity who reacted strongly if there was a bottle of beer open in a room, but who had no trouble with the Greek drink Ouzo. It illustrated that many CFS patients may not be alcohol sensitive, rather sensitive to complex hydrocarbons (i.e. aroma, etc) found in beer, wine and whiskies. On the other hand, a pure alcohol with a favoring does not cause a reaction.

I do find that I am extending this model to suggest that these low level chemical signatures may actually be triggering some species of gut bacteria to suddenly over-produce chemicals like histamines. This is speculation, but a 2002 article, Sellge G et al. Gram negative bacteria trigger human intestinal mast cells for histamine and cytokine production. In a 2008 article this same research identified an example E.Coli bacteria that demonstrate this, Selective activation of human intestinal mast cells by Escherichia coli hemolysin.


There were no direct PubMed articles on it’s impact on gut bacteria, glyceryl guaiacolate. We find a  anti-inflammatory and analgesic effect[1]. In terms of microbiome, there is almost nothing written, however known side-effects include diarrhea, and constipation[2]  which implies that it does impact the microbiome in some manner. It is related to Guaiacol which is broken down by gut bacteria in some species from plant material.

Salicylate and Bacteria

I know many CFS suffers who have moderate or severe salicylate sensitivities. I very greatly feel for them because this often prevents them from using herbs and other supplements that may improve their gut bacteria. A quick search on pubmed found 900+ articles with both of these words in them. A 2000 article describes the interaction of salicylates and bacteria:

“On one hand, growth of certain bacteria in the presence of salicylate can induce an intrinsic multiple antibiotic resistance phenotype. On the other hand, growth in the presence of salicylate can reduce the resistance to some antibiotics and affect virulence factor production in some bacteria. This review provides an overview of the effects salicylate has on various bacterial species.”

A 2012 study found that salicylates negatively impacts E.Coli (which CFS suffers are low in)

Bottom Line

It appears that all of the above influences gut bacteria. Whether it will make allow your good bacteria to be stronger, or encourage your bad bacteria is unclear.  We know that they impact the gut bacteria — and that is all that we know for sure.