Probiotics do nothing to help soothe babies with colic, according to the largest research trial to date.

Previous studies have suggested some benefit from giving infants probiotic drops, but they were flawed in their design, experts said.

In the latest study, a team set out to test the theory of whether probiotics would help breastfed and formula-fed babies with colic.

The results showed probiotics had no effect on reducing periods of crying or fussing among the babies, who were all under three months old.

Colic is a term used to describe infants who cry a lot but who are otherwise healthy and well fed.

The causes of colic are unknown although some theories suggest indigestion, trapped wind or a temporary sensitivity to proteins or sugars in breast or formula milk.

The condition affects up to one in five babies and usually begins within the first few weeks of life but often stops by the time the baby is four months old.

In most cases, the most intense period of crying occurs in the late afternoon or evening and usually lasts for several hours.

Parents often feel helpless because nothing they do helps to reduce their baby’s distress.

In the new study, 167 breastfed or formula-fed infants with colic were split into two groups.

The first group of 85 babies was given the probiotic Lactobacillus reuteri every day, which has previously been shown to help reduce crying.

The second group of 82 babies was given a placebo or ‘dummy’ solution.

The team of experts, including from the University of Melbourne and the Royal Children’s Hospital in Victoria, Australia, looked at several outcomes including duration of crying or fussing, how well the babies slept and how parents were coping.

They also examined the stools of infants to look at the effect of probiotics on the gut.

The results showed that, as time went by, the babies in both groups fussed and cried less. At one month into the study, babies in the probiotic group actually cried or fussed 49 minutes more than those in the placebo group. This mainly reflected more fussing, especially for babies who were being fed formula.

No differences were observed on all the other outcomes.

Writing online in the British Medical Journal, the team said probiotics “did not reduce crying or fussing in infants with colic, nor was it effective in improving infant sleep, maternal mental health, family or infant functioning, or quality of life”.

They added: “These findings differ from previous smaller trials of selected populations and do not support a general recommendation for the use of probiotics to treat colic in infants.”

In an accompanying editorial, William Bennett Jr, assistant professor of paediatrics at Indiana University School of Medicine in the US, said babies with colic “incur no serious long-term effects” from the condition and that symptoms “abate with time”.

As the old adage goes, “babies cry”, he said, adding that the passage of time, family support and reassurance may help parents and babies through the tough period.

Rosemary Dodds, senior policy adviser at the National Childbirth Trust (NCT), said: “This study reiterates that there is still sadly very little research to confirm the benefits of probiotics for babies with colic.

“Further research is needed to understand what helps babies and parents experiencing this worrying condition.

“Although it usually resolves within a couple of months, colic can be distressing for families. While there is no cure, there are things that parents can do that may help some babies and parents to cope.

“Babies who are bottle-fed can be ‘winded’ after a feed to help them bring up any air they take in with the milk; an upright position and gentle patting on the back is helpful.

“Babies who are breastfed need to be comfortably positioned at the breast, and finish the milk in the first breast before moving to the second.”