Is this the same thing as colic?

Largely, yes — colic is the older label (often defined as 3+ hours a day, 3+ days a week) for the same peak. The PURPLE framing exists because 'colic' made it sound like a disease, when the evidence points to a normal developmental phase nearly all babies pass through to some degree.

Does the crying mean my baby is in pain?

The face and sound often look pain-like at the peak — it's the P in PURPLE — but in a baby who feeds well, grows, and settles eventually, it usually isn't pain. If your baby also arches, vomits forcefully, or cries with feeds specifically, mention it to your pediatrician.

Nothing soothes them. Am I doing it wrong?

No — 'Resists soothing' is part of the definition. Soothing techniques are worth having, and sometimes they work; at the peak, sometimes nothing does, and that's the phase, not your technique.

When it happens · 4 min read

The crying peak nobody warned you about

It's 7pm, the baby has been crying for two hours, you've fed, changed, burped, rocked, shushed, and walked, and nothing works. Nobody told you this was coming, and the not-knowing is half the terror: is something wrong with the baby, or with you?

Usually, neither. What you're likely in is the peak of a curve that has a name.

Last updated August 9, 2026

The curve

Infant crying isn't random — across babies and cultures it follows the same arc. It increases starting around 2 weeks, peaks in the second month, and then falls away on its own by around 3 to 4 months. At the peak, long stretches of crying — often in the late afternoon and evening, often resistant to everything you try — are within normal. The acronym PURPLE describes the features: Peak of crying, Unexpected, Resists soothing, Pain-like face, Long-lasting, Evening.

Two things about this are genuinely freeing to know in advance. The crying often has no findable cause, so the endless diagnostic loop — gas? hunger? too hot? — sometimes has no answer because there isn't one. And it ends on its own, because it was a developmental phase, not a problem you failed to solve.

The one rule for your worst moment

There will be a night when nothing works and you feel something in yourself you don't like. That moment is normal too — and it has a protocol: put the baby down on their back in the crib, leave the room, and give yourself ten or fifteen minutes to breathe, call someone, or just stand outside the door. A crying baby alone in a safe crib is completely fine. Check on them every 10 to 15 minutes if you need to.

The reason this rule exists is stark: frustration with crying is the leading trigger for shaking a baby, and shaking — even briefly — can cause permanent brain injury or death. Never shake a baby. Putting them down safely and walking away isn't giving up; it's the thing a good parent does at the edge. Tell every caregiver — partner, grandparent, sitter — the same rule before they're ever alone with the baby.

When crying is a symptom instead

The curve explains crying in a baby who is otherwise well. Crying plus fever, vomiting, refusing feeds, fewer wet diapers, or a baby who seems to hurt when touched or moved is a different picture — call your pediatrician. And a sudden change — a baby who never cried like this before starting abruptly — is worth a call even without other symptoms, if only for your own certainty.

Common questions

Is this the same thing as colic?: Largely, yes — colic is the older label (often defined as 3+ hours a day, 3+ days a week) for the same peak. The PURPLE framing exists because 'colic' made it sound like a disease, when the evidence points to a normal developmental phase nearly all babies pass through to some degree.
Does the crying mean my baby is in pain?: The face and sound often look pain-like at the peak — it's the P in PURPLE — but in a baby who feeds well, grows, and settles eventually, it usually isn't pain. If your baby also arches, vomits forcefully, or cries with feeds specifically, mention it to your pediatrician.
Nothing soothes them. Am I doing it wrong?: No — 'Resists soothing' is part of the definition. Soothing techniques are worth having, and sometimes they work; at the peak, sometimes nothing does, and that's the phase, not your technique.

If it's this, not that

Newborn fever: why under three months is different →

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It answers from the same cited pages you are reading, and when the question is where to go, from the real clinician, hospital and childcare records behind this site — not a link to go search them yourself. It says so when we have not written about something, and it is not a doctor; for anything urgent it gives you the threshold and tells you to call.

Where this comes from

The Period of PURPLE CryingNational Center on Shaken Baby Syndrome

Every claim on this page traces to one of these. See every source we use →

Written from the sources named above, and it is not a substitute for your own doctor. If something feels wrong to you, that instinct is a good enough reason to call — you know yourself and this family better than any page does.