Actually, the problem lies in the long-tern use of these products. The vasoconstrictor used in them, usualy low concentrations of phenylepherine, do their job and constrict the vessles. But, after it wears off and has been used repeatedly, the vessels will acutally dilate larger than they would have been; had the problem been addressed initially and the symptom not been chronically treated there would be no problem. This is a more common problem then you may think.