I don't believe it's the Epsom Salts that cause the burning neither it's the acidic fruit juice.
Last time I had diarrhea for 1 week (not sure whether it was because of some flu or a detox reaction from taking H2O2) , in the last days the diarrhea also caused my ass to burn, after that the diarrhea was almost over.
Now doing the Liver Flush for the first time, I had only a few small green blobs (not really stones and the following bathroom trips were also really burning my ass, but I think this may be a good thing as I read this can be due to bile acids (and stomach acids).
I wonder if Hulda Clark or Moritz do not mention this burning ass symptom in their book?