Are you talking about matts? Depending on how bad they are she probably needs to be shaved down.
What kind of dog do you have and what type of basic grooming care have you been doing?
Matts are extremely painful. They twist the skin on the dog and it becomes very tender. I suggest, like Durb said, to take her to the groomer. You can see if they can de-tangle her coat is not she should be shaved down and you start over making sure you keep up with her grooming needs.
I've had to shave a few dogs that come in matted down to the skin and it takes a toll on the dog. It stresses them out so the best thing to do is to tak her in and have it done.
If you are referring to matts this should have been placed in the grooming section.
Welcome to DF.
