Vicks VapoRub has been popularly used to relive symptoms of common cold from many years.

Recent research revealed that it should not be used in the infants because the menthol-based ointment can cause a young child's airways to swell and fill with mucus, triggering severe breathing problems because of the small size of their nasal airways can cause airway inflammation that can restrict breathing in them.

Researchers from Wake Forest University started the study to see the effect of Vicks VapoRub in infants after treating 18-month-old girl who had developed severe respiratory distress after the salve had been put directly under her nose to relieve cold symptoms.

Researchers found that in ferrets which have airways similar to humans, Vicks exposure increased mucus secretion in both normal and inflamed airways. Moreover exposure to the product decreased the rate by which mucus was cleared from the trachea. The researchers added a high dose of VapoRub to windpipes that had been removed from ferrets killed for other research.

Lead author of the study Bruce Rubin said: "Those windpipes secreted 63% more mucus than windpipe specimens that had not been incubated with VapoRub."