Infant colic: what helps, and what the crying actually means

Colic is prolonged, intense crying in a baby who is otherwise healthy and feeding and growing normally; it is common, it is at its worst in the first six weeks of life, and it goes away on its own [s1][s3]. No treatment reliably cures it: the most-studied probiotic, Lactobacillus reuteri, modestly cuts crying in breastfed infants but not formula-fed ones, and there is no clear evidence that any probiotic prevents colic from starting [s2][s3].

What colic is — and is not

The working definition used in research is the "rule of three": full-force crying for at least three hours a day, on at least three days a week, for at least three weeks, in a baby who is well [s3]. That last clause matters. Colic is a description of a crying pattern, not a disease, and its symptoms are broad and non-specific; in a small share of infants excessive crying can signal an underlying problem that needs a medical assessment, which is why persistent or unusual crying is worth having checked rather than assumed to be colic [s3][s4].

The reassuring fact for exhausted parents is how predictable the course is. A meta-analysis of 28 diary studies covering 8,690 infants found that average daily fussing and crying held at roughly 117 to 133 minutes across the first six weeks, then fell to a mean of 68 minutes by 10 to 12 weeks of age [s1]. Measured against modified Wessel criteria, colic affected 17 to 25 percent of infants in the first six weeks, 11 percent by eight to nine weeks, and just 0.6 percent by 10 to 12 weeks [s1]. Notably, that review found no evidence for the widely repeated idea of a universal crying "peak" at six weeks — durations were broadly stable early on and then declined [s1].

Does anything treat it? The probiotic evidence

The single intervention with the best evidence is the probiotic Lactobacillus reuteri DSM17938, and even here the benefit is qualified. An individual-participant-data meta-analysis pooling four double-blind randomised trials of 345 infants with colic (174 given the probiotic, 171 placebo) found that treated infants cried and fussed less at every time point — an adjusted mean difference at day 21 of 25.4 fewer minutes a day (95% confidence interval 47.3 to 3.5 fewer) [s2]. The probiotic group was about 1.7 times as likely to reach treatment success (95% CI 1.4 to 2.2) [s2].

The crucial caveat is feeding type. The effect was substantial in breastfed infants — the number needed to treat for success at day 21 was 2.6 (95% CI 2.0 to 3.6) — but was not significant in formula-fed infants, for whom the authors said there were simply too few data to draw a conclusion [s2]. It is also worth naming that several authors of that analysis reported payments from probiotic manufacturers, a common feature of this literature that readers should weigh rather than ignore [s2].

Can you prevent it? Not clearly

Prevention is a separate question from treatment, and the answer is weaker. A Cochrane review of six placebo-controlled trials in 1,886 newborns found no clear evidence that giving probiotics from birth prevents colic: pooling three studies (1,148 infants), the risk ratio for new cases was 0.46 but its confidence interval crossed one (95% CI 0.18 to 1.19), on low-certainty evidence [s3]. Daily crying time was lower with probiotics — a mean of 32.57 fewer minutes across three studies (95% CI 55.60 to 9.54 fewer), and 44.26 fewer minutes in the L. reuteri subgroup — but the reviewers rated their confidence as low across all outcomes, meaning further research could change the picture [s3]. Serious adverse effects were rare and not different between groups [s3].

What guidelines advise

Because colic is self-limiting and drug treatments are largely ineffective, the mainstay of management in guidance is reassurance, support for the family, and help with feeding and coping rather than medicines; simethicone and similar over-the-counter remedies are not recommended for routine use [s4]. Guidance also stresses spotting the "red flag" features — such as poor weight gain, fever, vomiting or blood in the stool — that point away from colic and toward a condition needing assessment [s4].

The broader feeding context is relevant too. Questions about milk feeding and the introduction of solids are covered in our reviews of breastfeeding and the PROBIT trial and baby-led weaning versus spoon-feeding; reflux, a different cause of infant distress that in adults is often confused with it, is covered in our explainer on what actually causes reflux. Safe sleep practices, which matter most in exactly this age range, are set out in our guide to reducing the risk of sudden infant death.

How to read this

The honest summary is that colic is common, distressing and time-limited, and that the evidence for anything that shortens it is modest at best and confined largely to breastfed infants given one specific probiotic [s1][s2][s3]. What the data most clearly support is the natural history: crying that peaks early and reliably fades over the first few months [s1]. This article is informational and is not medical advice; a baby whose crying is severe, persistent, or accompanied by any warning sign should be assessed by a qualified clinician [s4].