nasal congestion
"I had the same issue as KimmerD30.  I love Afrin but after about a month from the purchase date, it takes on a mildewy smell even though the expiration date is at least a year away.  It makes me nervous about continuing to use it once this happens.  I keep the bottle on my nightstand so temperature is not an issue. Does anybody know what causes this and is it still safe to use once this happens?"