Vicks® VapoRub®, a menthol compound commonly used to relieve symptoms of cough and congestion, may create respiratory distress in infants and small children, according to new research out of Wake Forest University Baptist Medical Center.

Results of the study show that Vicks exposure increased mucus secretion in both normal and inflamed airways. Additionally, exposure to the product decreased the rate by which mucus was cleared from the trachea.

“The ingredients in Vicks can be irritants, causing the body to produce more mucus to protect the airway,” says lead author Bruce K. Rubin, MD. “Infants and young children have airways that are much narrower than those of adults, so any increase in mucus or inflammation can narrow them more severely.”

The current product labeling indicates that Vicks VapoRub should not be used on children under 2 years of age, which supports the study findings. However, many parents continue to use the compound on sick children, often applying it on the feet or chest.

The study is published in this month’s issue of the journal Chest.