Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was conducted according to a random computer‐determined allocation order considering birth weight"
Allocation concealment (selection bias)	Low risk	Quote: "Blinding was possible because the nursing staff who administered S. boulardii to the infants was not involved in the daily care and the attending neonatal team was unaware of the randomization assignments"
		Comment: Less likely that randomization sequence was revealed
Blinding of participants and personnel (performance bias)	Low risk	Quote: "Blinding was possible because the nursing staff who administered S. boulardii to the infants was not involved in the daily care and the attending neonatal team was unaware of the randomization assignments"
Blinding of outcome assessment (detection bias)	Low risk	Quote: "Blinding was possible because the nursing staff who administered S. boulardii to the infants was not involved in the daily care and the attending neonatal team was unaware of the randomization assignments"
Incomplete outcome data (attrition bias)	High risk	Quote: "25 (20%) patients were considered dropouts"
Selective reporting (reporting bias)	Low risk	Authors seem to report all the outcomes irrespective of their statistical significance
Other bias	Low risk	No other risk of bias was noted