Contant 2007.

Methods	Randomisation: computer‐generated randomisation list; participants were allocated to each intervention by means of numbered sealed envelopes that corresponded to the randomisation list. Blinding: none. Withdrawal/dropouts: 77 participants excluded. Follow up: 24 days (17 ‐ 34 days).
Participants	Inclusion criteria: indication for elective colorectal surgery with primary anastomosis. Exclusion criteria: acute laparotomy; laparoscopic colorectal surgery; contraindication for MBP; ileal stoma; younger than 18 years. Diseases: colorectal cancer, inflammatory bowel disease, radiation induced stenosis, endometriosis, correction of Hartmann's. Number: 1354 (682 male, 672 female). Age: mean age 67 years. Location of study: 13 participating hospitals in the Netherlands. Date: April 1998‐February 2004. Antibiotics: according to the guideline of each hospital: cefuroxime + metronidazole, cefazolin + metronidazole, cefamandole + metronidazole, gentamycin + metronidazole, amoxicillin + clavulanate, and others.
Interventions	Group A ‐ MBP (n = 670): PEG + bisacodyl (11 hospitals) or sodium phosphate solution (2 hospitals); fluid diet on the day before surgery. Group B ‐ normal meals (n = 684).
Outcomes	Anastomotic leakage: Group A = 32, Group B = 37. Wound infection: Group A = 90, Group B = 96. Fascia dehiscence: Group A = 19, Group B = 16. Urinary tract infection: Group A = 71, Group B = 70. Pneumonia: Group A = 39, Group B = 51. Intra‐abdominal abscess: Group A = 15, Group B = 32. Secondary intervention (reoperation): Group A = 58, Group B = 58. Mortality: Group A = 20, Group B = 26. Outcomes measured in days (postoperatives): Hospital stay: Group A = 10, Group B = 10. Resumption of normal diet: Group A = 6, Group B = 6. No postoperative complications: Group A = 462, Group B = 452.
Notes	A multicenter study. Sample size was calculated. By chance, more participants who smoked and had inflammatory bowel disease were allocated to MBP group. X² test or Fischer's exact test to compare complication rates between groups; Mann‐Whitney test to compare continuous or graded outcomes. Univariate analysis to asses the risk of anastomotic leakage. Multivariated logistic regression to test the risk factors simultaneously for any association with anastomotic failure. Multivariate analysis stowed that ASA classification, type of anastomosis and blood loss during operation were independent risk factors for anastomotic leakage. In 2010 subgroup analysis is published by van't Sant the authors of this review made the calculus: Colonic surgery (n = 905): Group A = 434; Group B = 471. ‐ Anastomotic leakage: Group A = 14; Group B = 23.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Low risk	A ‐ Adequate