The colon is the major re-absorber of water and the kidneys maintain the fine tuned, homeostatic water//electrolyte (Na+, K+, Cl-)balance with Renin, Angiotensin, Aldosterone, Natriurtic Protein controlling the mechanism to retain or excrete water and maintain proper water and ion balance. I read one message here from a lady who mentioned that she uses "purified water". I hope, by that, she does not mean distilled water. Throughout the body water travels on a concentration gradient; from a place of lower concentration of +ions to a place of higher concentration, inorder to try to equalize the the ions (usually Na+, H+, O2-) in both area.To illustrate with something more everyday for you contact lens wearers out there: the inside layer of the cornea is made up of cells that pump Na+ out of the cornea into the eyeball cavity. Now that space will have a higher concentration of Na+ and the water-sodium thrown off kilter. According to the laws of chemistry, water will then move out of the cornea to the area of higher Na+ in order to dilute the concentration to normal and balanced amounts. This keeps the cornea compact, clear and healthy. If those contacts are gunked up and old you get no O2 the drive the pump that that pushes the Na+ out of the cornea and then even worse things can happenn So, if one uses distilled water for an enema, which by definition has no Na,K,PO4 etc), the water injected is re-adsorbed through the colon wall into the circulation. If you are badly dehydrated with lots of Na+ in the circulation and not much water, that water is going to be sucked like a sponge back into you. Enteroclysis is the method of rehydration with a slow drip "enema". Not used much today. Hypodermoclysis is a slow drip, just under the skin, with a long needle, into both anterior thighs. If the patient has a heart condition, congestive failure, even uncontrolled hypertension, the water adsorbed from the enema can overload the circulatory system causing worse congestive failure. So, no distilled water and be careful of solutions. Nothing exotic including alcohol. Salt, NaCl made up of (in water) Na+, a positively charged ion and Cl-, a negatively charged ion. Class dismissed