Epsom Salts dilate the bile ducts and are essential for a safe flush. I have never heard nor read of problems relating to Epsom Salt intake.

Epsom Salts are perfectly safe, as you will soon see. Your unnecessary worrying will only lead to a lack of results. Relax!

One person wrote about it, but the general reaction was that it did not seem the reason was the ES. She had done a lot of things that had weakened her and she uses the ES as a reason.
Most of us use the ES, what is magnesium sulfate and not salt. You can read in the FAQ at the top of the page a few questions about ES.

If you don't want to use the ES read Julia Chang's website http://www.sensiblehealth.com

People that have calcified Gallstones sometimes use her protocol too but add 1tbs ES at night so the ducts will relax. But in your case since you are not doing the flush for Gallstones you can just do her flush.