It is the function of the liver to filter blood, remove toxic substances and excrete them in the solid waste.
The function of he kidneys is to maintain a balance of chemicals in he blood called electrolytes or sometimes salts. Urine is sterile and also full of unwanted nutrients rather than toxins.
When we Liver Flush the Epsom Salts pulls water from the large intestine and this increases the relative strength of the electrolyte solution in the blood. The kidneys then have to reduce the content of salts in the blood to maintain a balance. The kidneys need to be working satisfactorily to complete this task, other severe dehydration can occur. There are other factors that also effect our ability to regulate hydration. Aerobic individuals have thin cell walls and require both electrolytes and water to re-hydrate whereas non aerobic people only require water: in general.