What colic is

The NHS defines it by the clock: "All babies cry, but your baby may have colic if they cry more than 3 hours a day, 3 days a week for at least 1 week but are otherwise healthy." Raising Children Network uses the same rule and adds the crucial third clause — the crying "isn't caused by illness or injury."

Alongside the crying, the NHS lists: it is hard to soothe or settle your baby, they clench their fists, they go red in the face, they bring their knees up to their tummy or arch their back, and their tummy rumbles or they are very windy. Raising Children Network notes that faces "can turn red or purple, although this can be less noticeable in babies with dark skin", and makes a point worth holding onto: babies "might look like they're in pain, but this kind of crying isn't caused by pain."

How common, and how long

Roughly one baby in five. Raising Children Network says colic "occurs in about 20% of infants and is more common in the first 6 weeks of life." The AAP says "about one-fifth of all babies develop colic, usually between the second and fourth weeks."
It ends. The NHS: "It usually stops by the time they're 3 to 4 months old." The AAP says colicky crying generally stops by 3 to 4 months but can last until 6 months.
Even normal fussing peaks. The AAP notes that regular daily fussing "usually peaks at about 3 hours a day by 6 weeks old, and then declines to 1 or 2 hours a day by 3 to 4 months of age." Crying in the early evening is the norm, not a warning sign.

Nobody knows the cause. The NHS: "It's not known exactly what causes some babies to get colic." The AAP: "there is no definite explanation", though it suggests the child may be unusually sensitive to stimulation and unable to self-console.

What is worth ruling out first

Both the NHS and Raising Children Network say the same thing — before you accept "colic", rule out the things that look like it. Raising Children Network lists what a GP or paediatrician will consider: gastro-oesophageal reflux disease, infection such as an ear or urinary tract infection, hernia, allergy to cow or soy milk protein, and nappy rash or other sources of irritation.

It gives specific reasons to definitely see a GP: your baby seems listless or pale, is not feeding well or gaining much weight, has a fever, or has persistent vomiting or diarrhoea. If allergy is the cause, there are usually other signs — diarrhoea especially with mucus or blood, poor weight gain, screaming mostly around feeding, a lot of vomiting or vomit with blood, or hives or eczema.

What actually helps

The NHS's list is the practical core, and all of it is free:

Hold or cuddle your baby when they are crying a lot.
Sit or hold your baby upright during feeding, to stop them swallowing air.
Wind your baby after feeds.
Gently rock your baby over your shoulder.
Gently rock them in their Moses basket or crib, or push them in the pram.
Bath your baby in a warm bath.
Use gentle white noise, like the radio or TV, in the background.
Keep feeding as usual — the NHS is explicit that "you do not need to make any changes to your diet if you're breastfeeding."

The AAP adds walking your baby in a carrier, offering a dummy, laying your baby tummy-down across your knees and gently rubbing their back (then putting them in the cot on their back if they fall asleep), and swaddling.

What the evidence says about the remedies

This is where colic articles usually go wrong, so here it is straight.

Over-the-counter colic products. The NHS: "Remedies for colic, such as anti-colic drops, herbal or probiotic supplements, are available from pharmacies and some shops, but they're not recommended and there's no evidence they help colic." Raising Children Network is harsher: over-the-counter colic mixtures "have no scientific basis", are not recommended "because they don't work and/or haven't been thoroughly tested in young babies", and "might be harmful for your baby."

Probiotics. The Cochrane review of probiotics to prevent infantile colic included six trials with 1,886 participants. Its conclusion: "There is no clear evidence that probiotics are more effective than placebo at preventing infantile colic; however, daily crying time appeared to reduce with probiotic use compared to placebo." The reduction was a mean of 32.57 minutes per day (95% CI −55.60 to −9.54) across three studies, with a larger effect of 44.26 minutes in the Lactobacillus reuteri subgroup. The reviewers assessed the certainty of evidence as low across all three outcomes, meaning "we are not confident that these results would not change with the addition of further research." Raising Children Network's position is consistent with that: probiotics "might reduce crying in colicky babies, particularly breastfed babies", and it is worth discussing with a health professional rather than self-prescribing.

Spinal manipulation and cranial osteopathy. The NHS's advice is a "do not": "do not try putting gentle pressure to your baby's spine (spinal manipulation) or skull (cranial osteopathy) – there is little evidence this works, and it may hurt your baby." Raising Children Network: "Spinal manipulation isn't recommended for treating colic. Spinal manipulation might harm your baby."

Changing your diet or the formula. Raising Children Network says changing a breastfeeding mother's diet "is unlikely to reduce crying unless your baby is diagnosed with an allergy to something in your diet." On formula: "True milk allergy is uncommon in bottle-feeding babies... changing formula probably won't help with colic. Changes of formula can also be expensive." The AAP's figure is that "less than 5% of colicky crying is caused by food sensitivity."

Reflux medicine. Raising Children Network notes that although many babies with colic also have reflux symptoms, "there's no evidence that reflux medicine reduces crying and fussing."

Looking after yourself

This is not a footnote. Both the NHS and Raising Children Network treat parental coping as part of the clinical picture.

The NHS lists "you're finding it hard to cope" as a reason to call NHS 111 or see a GP, and gives the Cry-sis helpline (0800 448 0737, 9am to 10pm, seven days a week) as a free source of support. Raising Children Network says to see your GP or nurse if you or your partner has signs of postnatal depression, and to seek help if you feel you might hurt your baby.

And the one non-negotiable: never shake a baby. Raising Children Network: "It can cause bleeding inside the brain and likely permanent brain damage. If you feel like you can't cope, put your baby in a safe place like a cot. Try going to another room to breathe deeply." The AAP says the same. Putting a crying baby down safely and stepping away for a few minutes is the correct thing to do, not a failure.

When to call

Call your local emergency number (999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand) or go to the emergency department if:

Your baby has a weak or high-pitched cry.
Your baby's cry does not sound like their normal cry.

The NHS's framing is worth repeating: "You know better than anyone else what your child is usually like. Trust your instincts if you think something is seriously wrong."

Call NHS 111, your out-of-hours service or see a GP if: you are worried about the crying; your baby has colic and nothing seems to be working; you are finding it hard to cope; your baby is not growing or putting on weight as expected; or your baby still has symptoms of colic after 4 months of age.

Colic and Excessive Crying