Mechanical bowel cleansing is considered to be necessary prior to colorectal surgery, some radiological or endoscopic procedures, and for fecal disimpaction. Traditional bowel cleansing (TBC) with cathartics and enemas is a method of mechanical bowel cleansing for patients who have restrictive factors for whole-bowel irrigation (WBI), such as excessive fecal impaction, cardiac, hepatic or renal disorders. In this experimental study, TBC with hyperosmolar agents was evaluated in terms of their effects on colonic flora and bacterial translocation (BT). Sprague-Dawley rats were divided into 6 groups. The animals, except controls, were not fed for 72 h but received tap water ad libitum. During this period, lactulose, lactitol, sodium phosphate (NaP), polyethylene glycol 3350 (PEG3350) and physiological saline gavages were administered to the rats in groups 1-5, respectively, once a day. All animals except controls (group 6) received enemas with 15 ml of warm saline twice a day. The cecum, mesenteric lymph nodes (MLNs) and portal vein blood were sampled for microbiological and histopathological analysis. The highest level of coliform bacterial overgrowth and BT to MLNs were observed in the lactulose group, although the others, except the saline and control groups, also caused some degree of BT. Portal vein cultures were negative for all groups. Histopathological damage was not associated with cecal bacterial count and BT. As a result of this study, PEG3350 seems to be safer and more effective than lactulose, lactitol and NaP during TBC. Copyright (C) 2004 S. Karger AG, Basel.