Newborn · Crying
Baby Colic / PURPLE Crying
Recognise baby colic (Wessel's rule of 3s) and the normal Period of PURPLE Crying. What helps, what's been shown not to, and the red flags that are NOT colic.
Last reviewed 27 May 2026
Baby colic / PURPLE crying
Is this colic — and what helps?
⚠️ NOT colic — red flags
The Period of PURPLE Crying (Ronald Barr)
- Peak of crying around 6–8 weeks, then declines.
- Unexpected — timing unpredictable.
- Resists soothing — nothing reliably works.
- Pain-like face (but baby is not in pain).
- Long lasting — can total 5+ hours daily at peak.
- Evening — often worse late afternoon / evening.
PURPLE is normal infant crying behaviour, not a disorder. It exists across cultures and species — it’s neurodevelopmental, not parenting failure.
What sometimes helps (and what to try)
- The 5 S’s (Karp): Swaddle, Side-lying hold, Shushing (loud), Swinging (rhythmic), Sucking (pacifier or breast).
- Movement — pram walk, baby carrier, drive in the car, bouncy chair.
- White noise — vacuum, hairdryer, fan, white-noise machine.
- Skin-to-skin — especially for the witching hour.
- Warm bath — can interrupt the cycle.
- Probiotic L. reuteri DSM 17938 — some evidence in breastfed babies (Sung 2013 JAMA Pediatr meta-analysis), less clear in formula-fed. Discuss with your GP / health visitor.
- Anti-colic bottles + paced bottle-feeding if bottle-fed.
- Eliminate cow’s milk protein trial — only if other CMPA features (eczema, blood-streaked stool, vomiting, very strong family hx). Speak to GP first; mum eliminates dairy for 2–4 weeks if breastfeeding, or use hydrolysed formula. False-positive elimination is common; don’t restrict the maternal diet without evidence.
- Reflux medication — only with documented severe reflux (see /calculators/baby-reflux). NICE specifically advises AGAINST PPIs / H2 blockers for crying alone.
- Simethicone / gripe water — broadly negative trials but unlikely to harm; placebo effect for parents is real.
- Get a break. If you feel overwhelmed, put baby safely down in the cot, walk into another room for 5 minutes, breathe. Inconsolable crying is a documented trigger for shaken baby syndrome — the “walk away” safety message is in every PURPLE Crying programme.
Take a baby with crying + any of these to A&E / 999:
- Fever in a baby under 3 months (any temp ≥ 38 °C)
- Projectile or green / bilious vomiting
- Blood in vomit or stool
- Lethargic / floppy / hard to rouse between crying
- Non-blanching rash, bulging soft spot, stiff neck
- Difficulty breathing / blue lips
- Single crying spell > 4 hours straight
- You feel you might harm the baby
Common questions about colicky babies
- "Is it definitely colic, or could it be wind?" Tummy issues are over-diagnosed in colic. Crying after every feed with arched back + drawn-up legs is the classic colic posture — but it can also be silent reflux, CMPA, or simply normal crying behaviour. Address feeding mechanics first (latch, paced bottle), then look further if persistent.
- "What about hair tourniquet?" A single strand of mum’s hair can wrap around a baby’s toe, finger, or penis and cause hours of inconsolable crying. Always check carefully — especially if a baby suddenly screams. Easy fix once spotted; medical attention if the hair has cut in.
- "Should I cut out dairy / wheat / spicy food?" Without specific CMPA signs (eczema, blood in stool, vomiting), elimination diets in a breastfeeding mother rarely help colic alone and risk maternal nutrition. Discuss with an IBCLC or paediatric dietitian first.
- "My friend says her baby had reflux and PPIs fixed everything." NICE NG1 + AAP both advise AGAINST PPI / H2 blocker use for crying alone — trials show no benefit over placebo for irritability. Reflux medication is for documented severe vomiting + faltering growth + significant feeding aversion.
- "Will it damage my baby?" No. PURPLE crying is normal neurodevelopmental behaviour and does not harm babies. It damages parents’ sleep, mental health, and relationships — which is why support matters.
- "My partner doesn’t believe colic is real." Show them the Wessel criteria and PURPLE crying framework. Both parents benefit from understanding it’s a phase, not a behaviour problem.
- "How do I survive the witching hour?" Plan for it. Easier dinner. Stronger support adult on duty. Maybe take it in shifts. Walk outside. Movement + low light + skin contact + white noise stacked together work better than any single technique alone.
- "Is my baby in pain?" PURPLE-style crying produces a pain-like face but research suggests babies aren’t in actual pain — just unable to self-regulate the dysregulated state. Pain-presenting crying that’s constant + with vomiting or fever IS pain and needs review.
- "Postpartum depression and crying baby?" Strongly linked — constant crying is a known PPD risk factor. Screen mum (and dad) for depression with EPDS. Getting help for parental mental health helps the whole household.
- "How long does colic actually last?" Peaks at 6–8 weeks; 90% resolved by 12–16 weeks; 95% by 4 months. Persisting crying patterns past 4 months are NOT typical colic and need investigation.
- "What if I shake my baby?" If you feel you might harm your baby, put them safely in the cot, walk to another room, call a friend, call your GP, or call NSPCC (UK 0808 800 5000) / Childhelp (US 1-800-422-4453). Inconsolable crying is THE most common trigger for shaken baby syndrome — you’re not alone in feeling overwhelmed.
- "Does my baby cry less if I breastfeed vs formula feed?" No reliable difference for colic. Both groups follow the PURPLE curve. Don’t change feeding method just for crying.
Educational tool only — not medical advice. Fever in a baby under 3 months, projectile or green vomiting, blood in stool / vomit, lethargy, or breathing difficulty are emergencies — do not assume colic.
What does this mean?
About 1 in 5 healthy babies has a phase of intense crying that meets the classic “rule of 3s” (Wessel 1954, still the working definition): crying for at least 3 hours a day, 3 days a week, for at least 3 weeks, in an otherwise well baby. The pattern peaks at 6–8 weeks and resolves by 12–16 weeks in 90% of babies, regardless of what you try. Ronald Barr’s Period of PURPLE Crying framework (Peak, Unexpected, Resists soothing, Pain-like face, Long lasting, Evening) reframes this not as a disorder but as a normal neurodevelopmental phase — it occurs across cultures and species and is not caused by parenting. The hardest truth is that nothing dramatically shortens it. What does help is making it bearable: the 5 S’s (Karp — swaddle, side-lying hold, shush, swing, suck), movement, white noise, skin-to-skin, sometimes the probiotic L. reuteri DSM 17938 in breastfed babies (Sung 2013 JAMA Pediatr meta-analysis showed modest benefit). What doesn’t reliably help: anti-reflux medication for crying alone (NICE + AAP advise against), maternal elimination diets without specific CMPA signs, simethicone / gripe water. The most important safety message is walk away when overwhelmed: inconsolable crying is the most common trigger for shaken baby syndrome. Putting your baby safely in the cot and stepping into another room for 5 minutes is good parenting, not failure. Critical to know: certain signs are NOT colic and need same-day medical assessment — fever in any baby < 3 months, projectile or green vomiting, blood in stool or vomit, lethargy between crying spells, non-blanching rash, bulging soft spot, breathing difficulty, single crying spell > 4 hours, or new/worsening crying past 4 months. Always check for the hidden hair tourniquet (a single strand wrapped around a toe, finger, or genitals) — quick to find and fix, devastating if missed.
What is baby colic?
The classic definition (Wessel 1954, still standard): crying for at least 3 hours a day,3 days a week, for at least3 weeks, in an otherwise well baby. It's a description of a crying pattern, not a disease. Affects about1 in 5 babies.
How long does colic last?
Peaks at 6–8 weeks of age. 90% of babies are out of the pattern by 12–16 weeks; 95% by 4 months. The day-to-day intensity feels endless during it, but it has a definite end point in healthy babies.
The Period of PURPLE Crying
Ronald Barr’s framework normalises the experience:
- Peak around 6–8 weeks
- Unexpected timing
- Resists soothing
- Pain-like face (but not in pain)
- Long lasting
- Evening worse
PURPLE crying is normal neurodevelopment, not parenting failure.
What helps
- The 5 S’s (Karp): Swaddle, Side-lying, Shush, Swing, Suck.
- Movement — pram, baby carrier, car.
- White noise.
- Skin-to-skin contact.
- Warm bath.
- L. reuteri DSM 17938 probiotic (modest evidence in breastfed babies).
- Anti-colic bottles + paced feeding for bottle-fed.
What probably doesn’t help
- PPI / H2 blocker reflux meds for crying alone — NICE + AAP both advise AGAINST.
- Simethicone, gripe water — trials largely negative.
- Maternal elimination diets without CMPA signs.
- Switching formula without specific allergy features.
Red flags — NOT colic
- Fever in a baby < 3 months
- Projectile or green / bilious vomiting
- Blood in stool or vomit
- Lethargy / floppy between spells
- Non-blanching rash, bulging soft spot, stiff neck
- Breathing difficulty
- Single crying spell > 4 hours
- New / worsening crying past 4 months
Hair tourniquet — always check
A single strand of hair can wrap around a baby’s toe, finger, or genitals and cause hours of inconsolable crying. Easy to spot if you look; devastating if missed. Always check if a baby suddenly screams without other explanation.
If you feel overwhelmed
Put your baby SAFELY in the cot. Walk into another room. Breathe. Call a friend, family member, partner, or:
- UK: Cry-sis 08451 228 669, NSPCC 0808 800 5000
- US: Childhelp 1-800-422-4453
Inconsolable crying is the single most common trigger for shaken baby syndrome. Taking a break is good parenting.
Sources
- Wessel MA, et al. Paroxysmal fussing in infancy, sometimes called “colic”. Pediatrics 1954.
- Barr RG. The Period of PURPLE Crying. National Center on Shaken Baby Syndrome.
- American Academy of Pediatrics HealthyChildren. Colic.
- Sung V, et al. Probiotics to prevent or treat excessive infant crying. JAMA Pediatr 2013.
- NICE NG1. Gastro-oesophageal reflux disease in children and young people.
Frequently asked questions
What is baby colic?
The classic definition (Wessel 1954, still used): crying for at least 3 hours a day, 3 days a week, for at least 3 weeks, in an otherwise well-fed and healthy baby. It's a description of a crying pattern, not a disease. Affects about 1 in 5 babies, peaks at 6–8 weeks of age, and resolves by 3–4 months in 90% of cases.
How long does colic last?
Peaks at 6–8 weeks of age. 90% of babies are out of the colic pattern by 12–16 weeks; 95% by 4 months. The day-to-day intensity feels endless during it, but it has a definite end point in healthy babies. Persisting crying patterns past 4 months are NOT typical colic and warrant medical review.
What is the Period of PURPLE Crying?
Ronald Barr's framework (P-eak, U-nexpected, R-esists soothing, P-ain-like face, L-ong lasting, E-vening) describes the normal neurodevelopmental crying phase that peaks at 6–8 weeks. It's not a disorder — it occurs across cultures and species. The framework was developed to normalise the experience for parents and reduce shaken baby syndrome by emphasising the 'walk away when overwhelmed' safety message.
How do I soothe a colicky baby?
Karp's 5 S's are the most-used framework: Swaddle, Side-lying hold, Shush (loudly), Swing (rhythmic), Suck (pacifier or breast). Other helpful approaches: movement (pram walk, car ride, baby carrier), white noise (vacuum, fan, white-noise machine), skin-to-skin, warm bath. Stack multiple techniques — combined, they work better than any single one.
Does anything actually treat colic?
Most interventions don't reliably shorten the pattern. The probiotic L. reuteri DSM 17938 has modest evidence in breastfed babies (Sung 2013 JAMA Pediatr meta-analysis). Anti-reflux medication (PPIs, H2 blockers) is NOT recommended for crying alone (NICE + AAP). Simethicone and gripe water show no clear benefit beyond placebo. Maternal elimination diets help only when there are specific cow's milk protein allergy signs.
When is it NOT colic?
Fever in a baby < 3 months, projectile or green vomiting, blood in stool or vomit, lethargy between crying spells, non-blanching rash, bulging soft spot, breathing difficulty, single crying spell > 4 hours straight, or new/worsening crying past 4 months — these are NOT colic and need urgent medical review. Always check for a hair tourniquet (a single strand wrapped around a toe, finger, or genitals).
Could my baby's colic be cow's milk protein allergy?
CMPA can mimic colic — but specific features make CMPA more likely: eczema, blood-streaked stools, persistent vomiting, family history of atopy, or symptoms that started with cow's milk introduction. Without these, colic and CMPA elimination diets often don't help and risk maternal nutrition. Discuss with GP / paediatric dietitian before restricting.
I feel overwhelmed by the crying — what should I do?
Put your baby SAFELY in the cot. Walk into another room. Breathe. Call a friend, partner, family member, or your health visitor. In the UK, NSPCC (0808 800 5000); Cry-sis (08451 228 669). In the US, Childhelp (1-800-422-4453). Inconsolable crying is the single most common trigger for shaken baby syndrome — taking a break is GOOD parenting, not failure. You're not alone.
How does this relate to other calculators on BumpBites?
Companion: /calculators/baby-reflux for the reflux differential; /calculators/breastfeeding-latch for feeding mechanics; /calculators/postpartum-depression-quiz for parental mental health (heavily affected by colic); /calculators/sleep-regression for the related sleep upsets.