Hi Max, Thank you so much for bringing up this subject and for sharing your experience. Although I personally believe the EIS I make (about 10-12 ppm) is non-toxic, I can imagine that someone who has a problem with toxic metals in the brain or thyroid could be sensitive to large doses of EIS during the flu season or in winter. Homeopathy also comes to mind. As with all things, common sense and an inquisitive mind can take us far. I can see many possibilities for experimentation, including witch hazel, and will be testing some of these on myself Thank you. Best wishes, Carlene
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