This is the question from a recent meta-analysis (JAMA Pediatr 2013; 167: 1150-57 -thanks to Ben Gold for this reference).

Table 1 details the study designs, probiotic intervention, and outcomes.

Results: “Of the 12 eligible studies (1825 infants), 6 suggested that probiotics reduced crying and 6 did not…Meta-analysis of 3 small trials of breastfed infants with colic found that Lactobacillus reuteri markedly reduced crying time at 21 days…However, all trials had potential biases.”

In the three breastfed trials alluded to above, there were concerns regarding inadequate blinding of the intervention, unequal baseline characteristics, and use of non validated crying “diaries” which could be prone to recall bias.

More data are needed; fortunately there are several ongoing trials.

Bottomline (from the authors’ conclusion): “Although L reuteri may be effective as treatment for crying in exclusively breastfed infants with colic, there is still insufficient evidence to support probiotic use to manage colic, especially in formula-fed infants.”

Previous  related posts:

• Probiotics for Colic | gutsandgrowth This post has numerous references
• Colic Microbiome | gutsandgrowth
• How helpful are probiotics? | gutsandgrowth