Yes, I tried malic acid before a HC liver flush. I also ate several apples a day for months on end before a flush (not an HC flush - it was an olive oil, lemon juice flush without ES).
I don't get much out on my flushes, with or without ES, so I decided to try to 'nag' at the stones with a few different approaches: Pulverexx and chinese-type herbs, Rowachol-type supplements, turmeric, apples, parsley, etc.
I plan to do more LFs, but only after a few weeks of preparation.
It could be that detox was the cause of my reaction, but I've done lots of detoxing over the past few years and the GCG reaction was so different.
BTW, I get a similar reaction to plain (not organic) rooibus tea - there might be a connection there somewhere........