I got the defintition of toxic wrong, too – it has a specific meaning legally. Properly diluted GSE is classified as nontoxic. Of course, this “properly diluted” criterion can be applied to anything… that’s why an absolute measurement of the active ingredient fraction is desirable.

Also, “whether simple home extraction processes will produce the same efficacy” – the answer is clearly no, per the description of the synthesis on the Citricidal� website. More interestingly, the description of the active ingredient as a quaternary ammonium salt puts it in the same chemical family as several other widely used microbicides (though fortunately much less toxic).

The cited study (which does not examine antiviral or antiparasitic effects, only antibacterial) says that the extract is toxic to humans. Absolute concentrations of active agents are not given, meaning that controlling dosages would be impossible in practice (especally in water disinfection).

It may be argued that most uses involve only incidental exposure to tiny amounts, however given the rising concern over widespread exposure to traces of toxic chemicals, stating that the extract is “non-toxic” is dishonest.