Chen 2014.

Methods	Study design: randomised controlled trial Duration of the study, recruitment: 2006 to 2010 Country: China
Participants	Participants with colorectal cancer: age, mean ± SD: intervention group: 60.3 ± 17.2, control group: 59.8 ± 18.7
Interventions	Intervention (n = 35): combined Clostridium butyricum and Bifidobacterium capsule: 3 capsules, 3 times a day, administered from 5 days before to 7 days after surgery Control (n = 35): placebo All participants received intravenous chemotherapy (calcium folinate 300 mg, fluorouracil 500 mg) during surgery
Outcomes	Proportions of diarrhoea, all‐cause mortality, several other clinical outcomes (first postoperative exhaust time, first defecation time, incidence of abdominal distension, incidence of systematic inflammatory response syndrome (SIRS), time of intraperitoneal catheter drain, incidence of infection of incisional wound, incidence of pulmonary infection, incidence of urinary tract infection, time of fever, incidence of hypoproteinaemia, length of consumption of antibiotics, length of hospital stay, side effects relevant to drug), biochemical indices
Notes	Article written in Chinese
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The random sequence was generated through a random number table
Allocation concealment (selection bias)	Unclear risk	No relevant information
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo‐controlled trial with similar packaging of capsules
Blinding of outcome assessment (detection bias) Subjective outcomes	Unclear risk	Insufficient information for judgement
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	No information; however it is unlikely that assessment of objective outcomes (mortality) would have been influenced
Incomplete outcome data (attrition bias) Subjective outcomes	Unclear risk	Five participants in each group were excluded because of metastasis or non‐adherence to treatment strategy. Reasons for dropout were not specified per group
Incomplete outcome data (attrition bias) Objective outcomes	Unclear risk	Five participants in each group were excluded because of metastasis or non‐adherence to treatment strategy. Reasons for dropout were not specified per group
Selective reporting (reporting bias)	Unclear risk	No study protocol was available, but all outcomes prespecified in the methods section were reported in the results section
Other bias	Low risk	No indications of other bias