Colic is intense, inconsolable crying that follows a pattern: more than three hours a day, more than three days a week, for at least three consecutive weeks. This “rule of threes” is what pediatricians use to distinguish colic from normal newborn fussiness. If your baby is otherwise healthy, gaining weight, and feeding well but screaming for long stretches with no obvious cause, colic is the most likely explanation. It affects 10 to 30 percent of infants worldwide.
What Colic Looks Like
The crying itself has a distinct quality. It’s louder, higher-pitched, and more urgent than regular crying, and nothing you do seems to help. Your baby’s face may turn flushed or red. Their abdomen often feels tense and hard, their legs draw up toward their belly, and their fists clench tight. Some babies arch their back. The episodes can last anywhere from one to several hours, and they tend to follow a predictable schedule, most often hitting in the late afternoon or evening (sometimes called the “witching hour”).
Between episodes, your baby acts completely normal. They feed well, gain weight, and seem content. That’s one of the most confusing parts of colic: the dramatic contrast between the screaming and the stretches of calm.
When It Starts and When It Ends
Colic typically begins around two to three weeks of age and peaks at about six weeks. For most babies, the worst is over by three months, and symptoms resolve entirely by four to six months. That timeline can feel unbearable when you’re in the middle of it, but the condition is self-limiting. Your baby will outgrow it.
Colic vs. Reflux
Reflux is the other common suspect when a baby won’t stop crying, and the two can look similar. The biggest difference is timing. Colic episodes erupt on their own schedule, often in the evening, with no obvious trigger. Reflux discomfort is almost always tied to feeding. It peaks during or right after a meal and gets worse when the baby is lying flat.
Reflux happens because the muscle at the top of a baby’s stomach is still immature and doesn’t close tightly, allowing milk and stomach acid to flow back up. You’ll usually see frequent spitting up, though some babies have “silent reflux” where the contents come back up but get swallowed again instead of spit out. These babies may gag, cough, or refuse the breast or bottle. If the fussiness centers around feedings rather than appearing out of nowhere, reflux is worth investigating with your pediatrician.
Could It Be a Milk Allergy?
Cow’s milk protein allergy can cause symptoms that look a lot like colic: prolonged crying, gassiness, and general irritability. But milk allergy usually comes with additional digestive clues like diarrhea (sometimes with mucus or blood), vomiting, or skin reactions such as eczema or hives. If your baby is formula-fed, or if you’re breastfeeding and consuming dairy, and the crying comes with any of those extra symptoms, a milk protein allergy is worth discussing with your pediatrician. They may suggest an elimination trial where you remove dairy for a few weeks to see if symptoms improve.
Signs That Something Else Is Wrong
Colic is a diagnosis of exclusion, meaning it only applies once other causes have been ruled out. Certain red flags signal that the crying may have a medical cause that needs prompt attention:
- Fever in any baby under three months
- Vomiting that’s forceful or bile-colored (green)
- Sudden onset of intense crying in a baby who was previously calm, especially if it doesn’t let up at all
- Poor feeding or weight loss, or a baby who refuses to eat
- Lethargy or a baby who seems unusually limp or unresponsive between crying episodes
- Blood in the stool
- Abdominal swelling that doesn’t go away between episodes
Some causes of sudden, unexplained crying are surprisingly simple. A hair or thread wrapped tightly around a finger or toe (called a hair tourniquet) can cause intense pain and is easy to miss. A scratch on the cornea from a flailing fingernail is another one. If the crying pattern changes abruptly or something feels different from the usual episodes, trust your instinct and get your baby checked.
What Actually Helps
No single remedy reliably stops colic, but a combination of soothing techniques can reduce the intensity. The most widely recommended approach is the “5 S’s,” developed by pediatrician Dr. Harvey Karp. The idea is to recreate the sensory environment of the womb:
- Swaddle: Wrap your baby snugly in a blanket. The gentle pressure prevents the startle reflex from ramping them up further.
- Side or stomach position: Hold your baby on their side or tummy against your body. This is for soothing only. Always place them on their back for sleep.
- Shush: Make a loud, continuous “shhh” sound near their ear. It mimics the constant whooshing they heard in the womb and helps block out stimulating noise.
- Swing: Use slow, gentle, rhythmic movement. Rocking, bouncing on a yoga ball, or a car ride all work on the same principle.
- Suck: Offer a pacifier, bottle, or breast. Sucking triggers the release of endorphins, the body’s natural pain-relief hormones.
These techniques work best when used together, not one at a time. A swaddled baby held on their side while being gently bounced and shushed is getting four of the five at once.
For breastfed babies, a specific probiotic strain (Lactobacillus reuteri) has shown promise in clinical trials. A meta-analysis found that it significantly reduced crying time within the first week of use, with improvements continuing through four weeks. The evidence is strongest for breastfed infants; results in formula-fed babies have been less consistent.
The Toll on Parents Is Real
If colic is making you feel desperate, anxious, or defeated, that response is normal and well-documented. A study of 380 mothers found that those with colicky babies had significantly higher levels of depression, anxiety, and stress compared to mothers of non-colicky babies. As depression scores increased, mothers also reported feeling less bonded with their infants. The relationship goes both ways: parental stress can increase a baby’s fussiness, which increases parental stress further.
Exhaustion, guilt, frustration, and even fleeting thoughts of harming the baby are reported frequently enough that researchers consider them a known consequence of coping with colic. If you’re having those feelings, it doesn’t mean you’re a bad parent. It means you’re overwhelmed, and you need support. Putting your baby down in a safe space like their crib and stepping away for a few minutes is always an acceptable option. Asking a partner, family member, or friend to take a shift isn’t weakness. It’s how you get through the worst weeks.