AND RELEVANCE 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 , or to prevent infant crying .
IMPORTANCE  Excessive infant crying  is common , distressing , but without proven effective prevention or management options .
Probiotics may be a promising solution .
OBJECTIVE To examine whether probiotics are effective in the prevention/management of crying ( " colic " ) in infants 3 months or younger .
Probiotic Intervention in the First Months of Life: Short-Term Effects on Gastrointestinal Symptoms and Long-Term Effects on Gut Microbiota
Objectives : To determine whether probiotics administered for 6 months postnatally affect  gastrointestinal symptoms , crying  and the compositional development of the gut microbiota through infancy . Methods : The study comprised of 132 newborns whose mothers were r and omized to receive placebo or Lactobacillus rhamnosus GG ( ATCC 53103 ) before delivery . The treatments of mothers/infants continued for 6 months postnatally . A specific symptom chart was used to monitor gastrointestinal symptoms and infant 's crying during the 7th and the 12th weeks of life . Fluorescent in situ hybridization was used to establish the Bifidobacterium , Lactobacillus/Enterococcus , Bacteroides and Clostridium counts in fecal sample s at 6 , 12 , 18 and 24 months of age . Results : Numbers of different types of stools , vomits and crying time were comparable between the groups during the 7th and the 12th weeks of life . Dominant microbiota consisted of bifidobacteria throughout the study . At 6 months , there were less clostridia in faeces in the placebo compared with the probiotic group ( P = 0.026 ) , whereas after long-term follow-up at 2 years , there were less lactobacilli/enterococci and clostridia in faeces in the probiotic group than in the placebo group ( P = 0.011 and P = 0.032 , respectively ) , reflecting the impact of clostridia as a marker of microbiota succession in healthy infants . Conclusions : Probiotic administration in the first months of life was well tolerated and did not significantly interfere with long-term composition or quantity of gut microbiota
AND RELEVANCE 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 , or to prevent infant crying .
IMPORTANCE  Excessive infant crying  is common , distressing , but without proven effective prevention or management options .
Probiotics may be a promising solution .
OBJECTIVE To examine whether probiotics are effective in the prevention/management of crying ( " colic " ) in infants 3 months or younger .