Drain Problem

[jpompeo]

I am having a problem with my downstairs toilet flushing properly. My upstaris toilet flushes fine but when it is flushed there is a girgling sound in the downstairs toilet and a slight backwash of water in the downstairs shower. The water in the downstairs toilet when flushed rises all the way to the top of the bowl and then goes down quickly after a second or so. The shower downstairs also gets a small amount of water backed up into it whenever the downstairs toilet is flushed or when I do laundry. I am thinking I may have a clogged vent pipe and if I do, how do I clear it? The water that gets back up in the tub seems to have a lot of dirt in it?? Help!!

[Dean]

Sounds more like a clogged or partially clogged main sewer pipe to me.