A baby who cries inconsolably for hours, every evening, for weeks — despite everything you try — is one of the most gruelling experiences of early parenthood. This guide covers what colic actually is, why its cause is genuinely uncertain, an honest review of everything that has been tried as a treatment, and how to look after yourself through a phase that will, definitively, end.
😮💨 Open WiseMama — freeColic is defined by its pattern rather than its cause. The traditional clinical definition — sometimes called Wessel's Rule of Threes — describes crying for more than three hours a day, more than three days a week, for more than three weeks, in an otherwise healthy, well-fed baby. By this definition, it affects roughly 10–40% of infants, a range wide enough to reflect the genuine inconsistency in how it is defined and measured.
More recent criteria (the ROME IV guidelines) have moved away from the strict hours threshold toward a broader description of parental-perceived distress and fussiness — partly because counting hours of crying in a sleep-deprived household is not a reliable measurement instrument, and partly because the underlying experience that brings parents to their GP or health visitor is the same regardless of whether the stopwatch says two hours fifty minutes or three hours ten.
A phase of excessive crying in an otherwise healthy baby, typically beginning in the first 2–3 weeks of life, peaking around 5–6 weeks, and almost universally resolving by 3–4 months. Evening and night-time predominance is characteristic — hence the common term "evening colic," though crying can occur at any time. The baby appears to be in pain: drawing up the knees, arching, flushed face, clenching fists. There is no consistent identifiable cause, and nothing the parent does reliably stops it.
Colic is not caused by bad parenting, anxious parents, or feeding mistakes. It is not a sign that the baby is ill, damaged, or in persistent physical pain — though it looks exactly like that from the outside. It is not a permanent state. And it is not a diagnosis with a specific mechanism, which is why there is no specific cure — it is a descriptive label for a phenomenon whose cause remains genuinely uncertain.
It ends. Universally, by 3–4 months of age. This is a finite phase with a defined end point — not a permanent feature of your baby's temperament or your parenting. In the depths of week seven this is very difficult to hold onto. It is nevertheless true.
The Period of PURPLE Crying is a framework developed by paediatrician Dr Ronald Barr, grounded in extensive research into normal infant crying patterns across many cultures. It reframes excessive early infant crying not as colic — a medical label implying something is wrong — but as a normal, predictable developmental phase that all babies go through to varying degrees.
The PURPLE framework has two purposes. The first is to normalise — to tell parents that what they are experiencing is a phase of normal development, not evidence of illness or inadequacy. The second is more specific: the PURPLE period peaks at exactly the time when shaken baby syndrome is most likely to occur, because inconsolable crying in a sleep-deprived parent is the most common trigger. Understanding that the crying is normal, finite, and not caused by the parent reduces the risk of dangerous frustration responses. The programme has been adopted widely across paediatric services because the evidence for its effectiveness in preventing abusive head trauma is strong.
The honest answer to "what causes colic?" is that no one knows for certain, and any single explanation is probably wrong. This is not a satisfying answer when you are looking for something to fix — but understanding why the uncertainty exists changes how you think about the treatments on offer.
Gut immaturity. The gut of a newborn is still developing its motility, its enzyme systems, and its microbiome. Incomplete digestion, gas accumulation, and variations in gut movement may all contribute to discomfort. This is the basis for many of the dietary and probiotic interventions.
Gut microbiome differences. Several studies have found differences in gut bacterial composition between colicky and non-colicky infants — colicky babies may have lower levels of certain Lactobacillus species and higher levels of gas-producing bacteria. This is the mechanism proposed for the probiotic treatments that have shown some effect.
Neurodevelopmental immaturity. Colic timing coincides precisely with a period of rapid neurological development, and one prominent theory suggests it reflects the immature nervous system's difficulty regulating arousal states — transitioning between sleep and wakefulness, or managing sensory input. Under this model, colic is essentially a self-regulation problem during a phase when self-regulation is neurologically immature.
Family history of migraine. Studies have found a significant association between infant colic and parental migraine history — leading to the hypothesis that colic may be a migraine equivalent in the infant, driven by similar neurological mechanisms.
Trapped wind as the primary cause — the explanation most parents reach for — is probably not the main driver, despite being the basis for most over-the-counter colic remedies. Babies do swallow air and pass wind, and this can cause temporary discomfort. But the pattern of colic — its developmental timing, its evening predominance, its universal resolution at 3–4 months — doesn't fit a simple "too much gas" model. If wind were the primary cause, effective winding would reliably stop the crying. It rarely does.
This is the section most parents want. The honest answer is that the evidence for almost every colic treatment is weak, and nothing has been shown to reliably eliminate colic. What follows is the most accurate current picture — including what has the best evidence, what is harmless but probably not effective, and what to approach with caution.
This specific probiotic strain has shown consistent benefit in multiple randomised controlled trials, reducing daily crying time in breastfed infants with colic. A 2014 systematic review and meta-analysis found a significant reduction in crying duration compared to placebo. It is available over the counter in the UK (sold as BioGaia Protectis drops). The important caveat: the evidence is primarily in breastfed infants — trials in formula-fed infants have not shown the same benefit. It is harmless, relatively inexpensive, and worth trying for breastfed babies specifically.
Simethicone works by reducing surface tension on gas bubbles, theoretically making wind easier to pass. It is the active ingredient in Infacol and several other widely used colic remedies. The clinical trial evidence is consistent: simethicone does not perform better than placebo for infant colic. It is harmless, and many parents report it helps — the placebo effect in a distressed parent trying something is genuinely real. But there is no good evidence it reduces infant crying.
Traditional gripe water preparations (modern formulations no longer contain alcohol or sodium bicarbonate) have not been shown to be effective in clinical trials. They are harmless in approved formulations but their use is based on tradition rather than evidence.
Colief contains lactase enzyme, which breaks down lactose in breast milk before feeding. The rationale is that some infants may have relative lactase deficiency, leading to gas from undigested lactose. Some trials have shown modest benefit in breastfed infants. It is more cumbersome to use than other remedies (it needs to be added to expressed milk and left to work before feeding). Worth a trial in breastfed babies, particularly if there seems to be a clear feeding-related pattern to the crying.
Maternal elimination diets — cutting out cow's milk protein, cruciferous vegetables, caffeine, or other foods — have a very limited evidence base for reducing colic. The reasoning (that dietary proteins pass into breast milk and affect the baby's gut) has some biological plausibility, but the clinical trials are small and inconsistent. A trial elimination of cow's milk protein for 2–4 weeks is a reasonable experiment if you want to try something dietary and are committed to the discipline involved. There is no good evidence that cutting out vegetables, caffeine, or spicy food reduces colic.
For formula-fed infants, switching to a hydrolysed formula (where the cow's milk proteins are broken into smaller fragments) has some evidence behind it. If a formula-fed baby has colic alongside other signs suggestive of cow's milk protein intolerance — eczema, mucous stools, family history of allergy — a trial of hydrolysed formula is worth discussing with your GP. Soy-based formula is not recommended for infants under 6 months.
Chiropractic and cranial osteopathy are frequently suggested for colic and have a significant following among parents. The evidence from clinical trials is poor — studies are small, often unblinded, and inconsistent. NICE does not recommend these interventions for infant colic. The theoretical mechanisms are not well-established. That said, the treatments are low-risk if performed by a qualified practitioner experienced with infants, and some parents report improvement — though whether this reflects treatment effect, natural resolution, or parental reassurance is difficult to separate.
A gentle tummy massage — using the "I Love You" technique (stroking down the left side of the abdomen in I, L, and U shapes following the direction of the colon) — has some evidence for reducing crying duration and gas discomfort. It also has significant benefits for parent-baby bonding and maternal mood. Even where the evidence for colic-specific benefit is modest, it is something positive to do in a situation where parents often feel helpless.
While no strategy cures colic, several can reduce the intensity of a crying episode or shorten its duration. These work by meeting the baby's nervous system needs — not by treating a physical cause — which is why they help rather than solve.
Rhythmic motion — rocking, swaying, bouncing on a knee, pram or car rides — activates the vestibular system in a way that is inherently calming to young infants. The rhythm matters: steady and predictable tends to work better than irregular movement. Many parents find a specific motion that works for their baby — a particular speed, amplitude, or direction. A baby carrier or sling allows motion to continue while freeing the parent's hands.
White noise — a steady, mid-frequency shushing or rushing sound — mimics the acoustic environment of the womb and can calm an aroused infant nervous system. The volume matters: it needs to be loud enough to be heard over the crying, approximately the level of a running shower. A hairdryer, vacuum cleaner sound, or a white noise machine or app all work. The sound needs to be consistent rather than intermittent.
Non-nutritive sucking — on a dummy, a clean finger, or a feed if the baby seems hungry — activates the calming reflex. Even a baby who is not hungry will often settle temporarily with sucking, as the sucking reflex is deeply soothing neurologically in the first months of life.
Paediatrician Harvey Karp proposed that five simultaneous stimuli — Swaddling, Side or stomach position (while held, never for sleep), Shushing, Swinging, and Sucking — activate what he calls the "calming reflex." Used together, they are frequently effective in stopping crying that nothing else reaches. The mechanism is essentially flooding the nervous system with the vestibular, tactile, and auditory signals it associates with the womb environment.
A crying baby with a stressed parent in the room absorbs that stress. When a parent has been holding a crying baby for an extended period, their own nervous system is activated and their handling becomes less calm — which the baby senses. Passing the baby to another caregiver — a partner, grandparent, friend — often produces rapid settling simply because the new person is calmer. This is not a commentary on the primary caregiver; it is a physiological reality.
Fresh air and a change of scene work remarkably often — even in cold weather — for a reason that is not well understood. The sensory shift, the motion of the pram, the air temperature change, and possibly the effect of the outside environment on the parent all seem to contribute. When nothing else is working, going outside is worth trying.
Reflux is frequently diagnosed when a baby cries excessively, and colic is frequently assumed when it should be investigated further. Understanding the distinction matters — partly because the treatments are different, and partly because both over-treating reflux (with acid suppressants that have limited evidence and some risks in infants) and missing a condition that needs treatment are real problems.
Gastro-oesophageal reflux — stomach contents washing back up the oesophagus — is normal in young infants because the lower oesophageal sphincter is immature. Most babies reflux visibly: posseting (small milky possets after feeds) is entirely normal. If a baby is gaining weight well, feeding happily, and not distressed, reflux is present but not problematic and requires no treatment.
GORD describes reflux causing genuine distress and affecting the baby's wellbeing. The distinguishing features are: poor or faltering weight gain (the acid discomfort causes the baby to feed less effectively); feeding refusal or significant distress during feeds; arching away from the breast or bottle; and persistent distress that appears directly related to feeding rather than following the evening colic pattern. Importantly, GORD is significantly less common than the label suggests — it is applied to perhaps 1 in 300 infants but diagnosed in far more.
The most reliable single differentiator between colic and reflux as the primary issue is weight gain. A baby gaining weight normally, producing adequate wet and dirty nappies, and feeding with at least some periods of contentment is almost certainly not suffering from clinically significant GORD. Persistent poor weight gain alongside distress and feeding difficulty warrants investigation, including for reflux.
Both the Lancet and NICE have raised concerns about the over-prescription of acid suppressants (gaviscon, ranitidine, omeprazole, lansoprazole) in infants with normal crying. These medications have limited evidence of benefit for non-specific infant crying and carry some risks, including increased susceptibility to gut infections. A diagnosis of reflux should be based on clinical findings — particularly feeding difficulty and weight gain — not on crying alone.
Colic is a significant and under-acknowledged contributor to postnatal depression, relationship breakdown, and — in the most serious cases — abusive head trauma. Saying this plainly is not alarmism; it is an argument for taking the parental experience seriously rather than focusing exclusively on the baby.
Hours of inconsolable crying by a baby you cannot help, on top of sleep deprivation, physical recovery, and the emotional adjustment of new parenthood, produces a level of stress that is physiologically similar to acute trauma. Feelings of failure, inadequacy, resentment of the baby, and desperate helplessness are normal responses to this situation — not signs of poor parenting or postnatal illness. They become clinical concerns when they are persistent, when they affect your ability to care for yourself or the baby, or when they escalate toward something dangerous.
If you are at the point where you feel you might do something to hurt your baby — shake them, squeeze them, do anything to make the noise stop — put the baby down in their cot or pram (on their back, in a safe position), leave the room, and give yourself five minutes. Check on them regularly. Call someone. A briefly crying baby left safely in a cot is not harmed. A baby shaken in a moment of desperate frustration can be profoundly and permanently harmed. The ability to put the baby down and walk away is not a failure of love. It is an act of love.
Colic is not a private endurance test. Ask your partner to take the baby for the difficult evening hours consistently. Accept offers of help from family or friends. If you are doing this alone, speak to your health visitor about what support is available. The Cry-sis helpline (08451 228 669, 9am–10pm daily) is staffed by parents who have been through this and provides immediate, non-judgmental support for parents of persistently crying babies.
Speak to your GP or health visitor if: you are experiencing persistent low mood, anxiety, or intrusive thoughts; you are not coping with basic daily function; or you are worried about your own responses to the baby's crying. Postnatal depression and anxiety are both more common in parents of colicky babies, and both are treatable. Asking for help is not an admission of inadequacy — it is the right clinical response to a difficult situation.
My daughter cried for five hours every evening from week three to week eleven. I genuinely thought something was wrong with me as a parent, and something was wrong with her. Week twelve she just... stopped. I wished someone had told me very firmly at the start: this will end at around three months. Because I genuinely didn't believe it was temporary.
Colic is a diagnosis of exclusion — it should only be applied once other causes of excessive crying have been considered. Most of the time, by the time parents reach their GP, colic is the correct explanation. But some presentations warrant clinical assessment to rule out other causes.
• Has a fever (38°C or above in a baby under 3 months needs same-day assessment)
• Has a high-pitched, unusual, or distinctly different cry from their normal crying
• Is not gaining weight or has lost weight
• Has blood in their stools or vomit
• Has bile-stained (green) vomit — this is always urgent
• Has a distended (swollen) abdomen
• Is unusually difficult to rouse or seems floppy
• Has crying that started suddenly and severely rather than building gradually
• Has associated symptoms — rash, persistent diarrhoea, visible distress specifically during or after feeds
The pattern of colic is gradual onset from the first weeks, peak at 5–6 weeks, and gradual resolution. Crying that starts suddenly and severely in a previously settled baby, or that is accompanied by any of the above, needs assessment.