The folk remedy did better than cough medicine or no treatment in a three-way comparison. Honey may work by coating and calming an irritated throat, the study authors said.
"Many families are going to relate to these findings and say that grandma was right," said lead author Dr. Ian Paul of Pennsylvania State University's College of Medicine.
The research appears in December's Archives of Pediatrics and Adolescent Medicine
U.S. health advisers have recently warned that over-the-counter cough and cold medicines should not be used in children younger than 6, and manufacturers are taking some products for babies off the market.
Three pediatricians who read the study said they would tell parents seeking alternative remedies to try honey. They noted that honey should not be given to children under age 1 because of a rare but serious risk of botulism.
For the research, researchers recruited 105 children with upper respiratory infections from a clinic in Pennsylvania. Parents were given a paper bag with a dosing device inside. Some were empty. Some contained an age-appropriate dose of honey-flavored cough medicine containing dextromethorphan. And some contained a similar dose of honey.
The parents were asked about their children's sleep and cough symptoms, once before the bedtime treatment and once after. They rated the symptoms on a seven-point scale.
All of the children got better, but honey consistently scored best in parents' rating of their children's cough symptoms.
"Give them a little time and they'll get better," said Pat Jackson Allen, a professor at Yale University School of Nursing.
The study was funded by a grant from the National Honey Board, an industry-funded agency of the U.S. Department of Agriculture. The agency had no influence over the study design, data or results, Paul said.