Experts say it should not be used on children under 2 years of age.
Vicks VapoRub, a salve which can be bought over the counter, is used to relieve coughs and congestion, but can apparently harm infants and toddlers.
According to Dr. Bruce Rubin from Wake Forest University School of Medicine, Vicks VapoRub can have severe effects on breathing in young children because it may stimulate mucus production and airway inflammation.
The product made by Procter and Gamble has been around since 1905 - it is applied to the chest or throat for congestion relief or to relieve sore muscles.
It contains camphor which is toxic if swallowed or absorbed into the body and the manufacturers do in fact warn that VapoRub should not be applied in or near the nostrils and not used on children under 2 years of age.
Dr. Rubin was first alerted to the dangers of the misuse of the Vaporub when an 18-month-old child developed severe respiratory distress after it was put directly under her nose.
Dr. Rubin says the ingredients in Vicks can be irritants, causing the body to produce more mucus to protect the airway, and 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.
Research was then carried out on the effects of the salve on the respiratory system of animals - ferrets, which have an airway system similar to humans, were used and tests conducted which measured the effects of the Vaporub on mucus secretion and build up in the airways, and fluid build-up in the lungs.
It was found that the Vaporub increased the mucus secretion and decreased the clearance of the mucus and Dr. Rubin says Vicks should not be put in or under, the nose of adults or children and never used in children under age 2.