Table 1.

Characteristics of trials included in the analysis

Study/year/reference	Description/study design	Birth weight and age at enrolment	Probiotic agent(s)	Dosage and duration	Control arm	Primary outcome
Savino/2007 [24]	April 2004 - May 2005.	Birth weight 2500-4000 g and aged 21–90 days	L. reuteri (American Type Culture Collection Strain 55730)	108 colony-forming units in 5 drops for 28 days	Simethicone	A reduction of average crying time to less than 3 hours a day on day 28.
	90 exclusively breastfed infants with a diagnosis of infantile colic.
	Recruited in the Department of Pediatric and Adolescence Science (Regina Margherita Children Hospital, Turin, Italy)
	Open prospective randomized study.
Savino/2010 [25]	March 2008 and August 2009.	Birth weight 2500–4000 g and aged 2–16 weeks	L. reuteri DSM 17938	108 colony-forming units in 5 drops, once a day, 30 minutes before the feed in the morning, for 21 days	Placebo	A reduction of average crying time to less than 3 hours a day on day 21.
	50 exclusively breastfed infants were recruited from general pediatricians and outpatients at the Department of Pediatrics, University of Turin (Regina Margherita Children Hospital)
	A Randomized, Double-Blind, Placebo-Controlled Trial
Szajewska/2013 [26]	January 2010 and December 2011.	Full term infants aged <5 months	L. reuteri DSM 17938	108 colony-forming units in 5 drops, orally, once a day, for 21 days	Placebo	The percentage of children achieving a reduction in the daily average crying time more than 50% and the duration of crying at 7, 14, 21, and 28 days after randomization.
	80 exclusively or predominantly (>50%) breastfed infants
	Family primary care practice in Warsaw, Poland
	A Randomized, Double-Blind, Placebo-Controlled Trial

Colic in all the trials was defined as crying episodes lasting ≥3 hours/day and occurring at least 3 days/week within 7 days prior to enrollment.