What Is Colic in Babies and How to Recognize It? | The 3-3-3 Rule Explained

Colic in babies is frequent, intense crying in an otherwise healthy infant — the standard definition is 3+ hours a day, 3+ days a week, for 3+ weeks.

A baby who screams every evening no matter what you try has probably already been checked out and declared perfectly healthy. That is the puzzle of colic: nothing is wrong, and your baby is still miserable. Crying typically starts around 2–3 weeks of age, peaks near 6 weeks, and eases off somewhere between 3 and 4 months.

Below is how to recognize it, what actually soothes a colicky baby, and the red flags that mean you should call a doctor instead of waiting it out.

What Is Colic and How Do You Recognize It?

Colic is a diagnosis of exclusion: prolonged crying in a healthy baby that has no identifiable medical cause.

Mayo Clinic’s criteria are the ones most clinicians use — crying for 3 or more hours a day, 3 or more days a week, for 3 or more weeks. The crying is usually loud and intense, often with no obvious trigger, and often lands in the evening.

Babies with colic often pull their knees up, clench their fists, arch their back, and turn red in the face. Swaddling, feeding, or rocking that works on other days may do nothing on a bad night — seeming inconsolable is part of the picture, not proof you are doing something wrong.

Why Does Colic Happen and When Does It Peak?

No one knows exactly what causes colic, though swallowed air during feeding is a common contributor. Symptoms often start at 2–3 weeks of age, peak around 6 weeks, and resolve by about 3 to 4 months — the timeline is the most predictable thing about it.

Simple steps that can help during this window:

• Upright feeds. Hold your baby upright while feeding to reduce how much air is swallowed.
• Burp often. Burp after every feed, not just at the end.
• Bottle geometry. If you bottle-feed, a curved or collapsible-bag bottle can cut down on air intake.
• Comfort measures. Try swaddling, rocking, a stroller walk, a warm bath, white noise, or a pacifier — one may work when another doesn’t.

One thing you can skip: changing a breastfeeding parent’s diet. There is no evidence it helps colic, and it just adds stress to an already hard stretch.

When Should You Call a Doctor?

See a pediatrician if your baby’s cry sounds abnormal — weak, high-pitched, or unlike their usual cry — or if you are simply worried your baby may be ill.

Urgent evaluation is warranted if your baby isn’t growing well or is still symptomatic after 4 months old. Beyond that, be cautious with every “colic remedy” on the market: OTC simethicone has not been shown to help, routine probiotics are not generally recommended, and other medications carry real side effects. Talk to a clinician before giving your baby anything — that conversation matters more than any product review,

read the Mayo Clinic colic treatment guidance for the full official checklist.

If you want to see how various OTC colic products stack up against each other — and which ones clinicians actually warn against — our tested guide to colic medicine options breaks them down.

Patiently working through the comfort measures above while waiting out the peak is the standard approach, and it genuinely helps most families — not because it silences the crying, but because it keeps everyone steady until the phase passes.