Most colon cleansing regimens for surgical and diagnostic procedures such as colonoscopy are modifications of older barium enema X-ray preparations which have evolved in gastrointestinal laboratories influenced by empiric experience. Recent formal study allows for careful comparison of gut lavage, diet and cathartic, and oral sodium phosphate preparations. This review will evaluate oral lavage solutions and address their safety, tolerance and efficacy. Administration options are discussed as well as other diet and cathartic methods previously referred to as 'standard preps'.