sewer odor

I have an odor in my bathroom. It smells very much like sewage. The smell is stronger at times...like after showering. What do I need to do to eliminate this problem? Is this something I can take care of or should I call in a professional?
Thanks!
Lbarber

I would check your traps first.
Is there standing water in them preventing smell from coming up?

Then I would check the toilet seal.