Others contain oral phenylephrine and acetaminophen, dextromethorphan or another active ingredient. ExploreFDA says key ingredient in Sudafed, Vicks and Benadryl products doesn’t work “It is the FDA’s ...

Essentially, decongestants work to shrink swollen blood vessels in the nasal cavity, which is what causes congestion. Caffeine, also found in tablets like Sudafed, can have a similar effect.

The active ingredient in a number of popular over-the-counter decongestant tablets and syrups doesn't actually work, an FDA advisory panel concluded on Tuesday, so you may be wondering where to ...