clogged vent?

[bwatty]

The bathroom sink in one bathroom upstairs and in the bathroom directly below it give a strong sewer odor whenever used:eek:. I have tried using enzymatic cleaners to remove sludge from the lines, but to no avail. The problem seems to be worse in cold weather, but it never goes away completely.

Is it probable for the vent lines to clog. If so what is the easiest way to clear them.

[Deb]

It is most likely not sewer smell and not related to a vent, clogged or not. It is most likely icky nasty stuff in the overflow.
Deb
The Pipewench

[bwatty]

Deb. I'll try un-gunking. :D