A probiotic, Lactobacillus reuteri DSM17938 (L.r.), helped breastfed infants with colic. Now you have something readily available over-the-counter to help a desperate family with a colicky but otherwise normal baby.
Why does this matter?
Colic is defined as crying >3 hours per day >/= 3 days per week. It is bewildering for parents and for those of us who try to help them get through it. It not only makes parents frustrated, it is associated with increased postpartum depression and, tragically, an increased risk of abuse. Having something in our treatment arsenal that actually works is not just welcome but may save a life.
Will he ever stop crying?
As a dad, I can say - colic is no fun. Having a baby that cries no matter what you do is incredibly difficult. This was a meta-analysis of double-blind RCTs that compared L.r. (0.2 × 10^8 colony-forming units per drop, 5 drops orally per day) to placebo. They performed an individual participant data meta-analysis, "which pools raw data from individual studies to create sufficient power to produce more reliable estimates of treatment effects." They found that in breastfed infants, it reduced crying time by 46 minutes a day. The NNT for success at day 21 in breastfed infants was 3. There was not enough information to draw conclusions in formula fed infants. Confidence intervals were significant but wide, even with this pooled meta-analysis. But at least we have some evidence that this works and appears safe.
Lactobacillus reuteri to Treat Infant Colic: A Meta-analysis. Pediatrics. 2018 Jan;141(1). pii: e20171811. doi: 10.1542/peds.2017-1811.
Peer reviewed by Thomas Davis, MD.