Traditionally, polyethylene glycol (PEG) solution, which requires ingestion of a large volume of liquid, has been used and now to a low-volume preparations because of its clear advantages in tolerability. The tolerability of bowel preparations is related to their volume, taste, and side effects, with this being a particular problem in the elderly. Meanwhile, a new oral sulfate solution (OSS, SUPREP, Braintree Laboratories, Braintree, Mass) formulation as an effective low-volume bowel cleansing agent, with a split-dose regimen was recently developed in 2009.