The powder and mixture for oral intestinal lavage solution (called Polyethylene glycol-electrolyte lavage solution: PEG-ELS) used for pre-treatment of endoscopy of the large intestine were prepared. The pH, buffer capacity, and viscosity were almost constant for maximum 21 days under three conditions (5°, 20°, and 30°).Any ingredients of powders and mixtures were almost stable for 21 days. Bacteria (S. aureus) proved to be hard to propagate in the mixture. The patients and physicians used the PEG-ELS evaluated the convenience, efficacy and easily of the mixture.
