Cough syrup may not be the miracle medication that parents have used for decades to quiet their hacking children and give everyone a good night of sleep. Researchers from the Pennsylvania State College of Medicine tested two common cough syrups against a nonmedicated syrup to see how well each stopped children's coughing for a night.

What the researchers wanted to know: Are over-the-counter medicines an effective treatment for children with a cough caused by an upper respiratory tract infections, a common cause of coughing?

What they did: The researchers recruited 100 patients, all between the ages of 2 and 16, who had coughs caused by nonchronic respiratory tract infections and who had not taken medication for their coughs the day before they participated in the study. Parents were given a questionnaire asking them to rate the severity and frequency of coughs and to say how much the coughing affected the child's and parent's sleep. That night, without knowing what they were taking, children swallowed a dose of dextromethorphan, diphenhydramine (two common cough medications), or a benign syrup. The next day, parents were given the same cough questionnaire again.

What they found: Overnight, all of the participants in the study coughed less and slept better, but the surprising thing was that the medicated syrups did no better than the nonmedicated one. The only significant differences were increased insomnia in patients who took dextromethorphan and increased drowsiness in patients who took diphenhydramine.

What it means to you: As one of the most common causes of hospital visits for both children and adults and an ailment typically treated with over-the-counter medications, coughing costs consumers billions of dollars per year. This study recommends that we spend our bills a bit more wisely, letting nature run its course or just using a hot cup of tea instead of expensive cough medications.

Caveats: The study measured only the change in coughing after one night of taking medications, so it is possible that taking them over several days would have showed a difference between the medication and a placebo.

Find out more: WebMD has a good website that offers tips to alleviate coughing without medication.

Read the article: Paul, I.M., Yoder, K.E., Crowell, K.R., Shaffer, M.L., McMillan, H.S., Carlson, L.C., Dilworth, D.A., and C.M. Berlin. "Effect of Dextromethorphan, Diphenhydramine, and Placebo on Nocturnal Cough and Sleep Quality for Coughing Children and Their Parents." Pediatrics. Vol. 114, No. 1, pp. e85–e90.

Abstract online: http://pediatrics.aappublications.org