The only problem that I am aware of with Epsom Salts is the potential for dehydration and electrolyte imbalance. If dehydration occurs there is a higher concentration of toxins in the body due to fewer fluids to dilute them. Any salt...sea, too...in higher concentrations can cause this to happen. Though certainly not always the case, I think the reason many people feel bad following the flushes is because of dehydration and lack of electrolytes. Most people are chronically low-grade dehydrated to begin with and the Epsom Salts just makes it worse.