Epsom salts, grapefruit, and olive oil...?

How exactly does epsom salt, grapefruit, and olive oil help flush the liver of gallstones? I've heard from a pathologist that if you know your chemistry you'll know that these three ingredients mixes in the stomach to actually create the stones being flushed. I'm just wondering why exactly Epsom Salts , grapefruit, and olive oil does the work. Anyways, i'm also wondering where can i purchase Epsom Salts ? What exactly is epsom?

Thanks,
Kev Tweet