Moral 2009.

Methods	Randomisation: sealed envelops. Blinding: not described. Withdrawal/Dropout: not described. Follow‐up: 30 days after surgery.
Participants	Inclusion criteria: elective colorectal surgery with primary anastomosis. Exclusion criteria: colorectal cancer smaller than 2 cm not marked by colonoscopy, those who were found to have an abscess of the tumour, diverticulitis, patients who refused to be randomised. Diseases: benign and malign colorectal diseases. Number: 139 (50 male; 89 female). Age: 68 ‐ 70 years. Location: Barcelona, Spain Time: May 2005 ‐ Agost 2007. Antibiotics: ‐ Oral (single dose 24 hours before the surgery): neomycin + metronidazole; ‐ Parenteral (single dose at the induction of anaesthesia): ceftriaxone + metronidazole.
Interventions	Group A ‐ MBP (n = 69): monobasic sodium phosphate + dibasic sodium phosphate or polyethylene glycol Group B ‐ no MBP (n = 70): 2 cleansing enemas ‐ the day before the surgery (at 21:00 PM), ‐ 2 hours before the surgery.
Outcomes	Overall anastomotic leakage: Group A = 5; Group B = 4 ‐ colorectal anastomosis: Group A = 0 (in 31 patients); Group B = 3 (in 19 patients), ‐ colonic anastomosis: Group A = 5 (in 38 patients); Group B = 1 (in 51 patients). Mortality: Group A = 2; Group B = 0; Overall wound infection: Group A = 8; Group B = 4 ‐ colorectal surgery: Group A = 3 (in 31 patients); Group B = 0 (in 19 patients), ‐ colonic surgery: Group A = 5 (in 38 patients); Group B = 4 (in 51 patients).
Notes	Sample size was calculated. Colonic anastomosis: Group A = 38; Group B = 51; Colorectal anastomosis: Group A = 31; Group B = 19.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Low risk	A ‐ Adequate