A bit of sugar on the tongue may help distract a baby from the pain of an injection, and cuddling and cooing probably helps, too. But according to a new study, the most effective way to reduce the infant’s pain is to apply lidocaine cream at the injection site as well.

Researchers randomized 352 babies under a year old to four regimens: a placebo (telling parents to do what they think best); an educational video about infant soothing; the video plus orally administered sucrose; and the video, sucrose and topically applied lidocaine to numb the pain. The study is in the Canadian Medical Journal.

Parents calculated the infants’ pain on a zero-to-10 scale based on facial grimacing, crying and body movements.

With injections at ages 2 months, 4 months, 6 months and 1 year, the group that got the lidocaine swab consistently had lower pain scores. Scores in the groups that got sucrose and videos did not differ from those in the placebo group at any age.

According to the lead author, Anna Taddio, a professor of pharmacy at the University of Toronto, the lidocaine swab has no serious side effects when used as directed.

“We should try harder to get it used,” she said. “It’s the only thing that we know works reliably, and we should make a better effort to use it so kids can benefit.”