After we posted the news yesterday that the iconic Vicks VapoRub may be dangerous to tots, readers asked a good question: Would a Vicks baby formulation cause the same potential breathing problems described in a study in this week's issue of the journal Chest?

That research—conducted on ferrets after a handful of congested toddlers who used VapoRub were brought into the hospital—suggested that ingredients in the ointment may trick the body into producing excess mucus to protect the airways from what the brain perceives as cold air. Menthol produces that cooling sensation, and it—or the other two ingredients—could trigger the inflammatory response, said Bruce Rubin, the Wake Forest University pediatrician who conducted the study. While likely harmless to older VapoRub users with wider airways, the extra mucus could dangerously narrow the airways of kids under two, he said.

VapoRub manufacturer Procter & Gamble does advise consumers not to use the salve  on youngsters under two years of age. But it makes another, non-medicated product, Vicks BabyRub, for babies three months and older. It contains petrolatum, fragrance, aloe extract, eucalyptus oil, lavender oil and rosemary oil—but not menthol or camphor.

Rubin tells us he didn’t study BabyRub, and notes the difference in its composition from VapoRub. "For those reasons, I really don't know and can't speculate if it would do the same," he says.

A spokeswoman for P&G, Paula Koenigs, says BabyRub is designed to soothe a fussy baby—and not, like VapoRub, to relieve the symptoms of colds and coughs. "We aren't convinced that it’s the VapoRub that caused the problem [reported in Chest] in the first place," Koenigs says. "I don't know how to answer if BabyRub would cause that same problem."

The Food and Drug Administration didn’t immediately respond to a question about whether it had received any adverse-event reports about BabyRub. P&G reports fewer than three adverse events per million units of VapoRub sold—usually mild, self-resolving skin irritations. The company hasn't received any reports of serious breathing problems with Vicks BabyRub use, Koenigs says.

But she adds that it's an apples and oranges comparison between the two products. "It's like, 'Do you have [health] problems if you put hand lotions on?'" she asks rhetorically. With BabyRub, "We're not talking about medicated therapy."

Updated at 5:35 p.m. January 14 with P&G reporting no serious respiratory problems from Vicks BabyRub.