Why is there smoke in my house when I use my fireplace?

Its because your chimney is not in a proper working order. The reason for the smoke is some kind of dirt/debris or it could even be nests of birds of broken branches of tree that are blocking your chimney. You can efficiently clean you chimney if you haven't. I'm giving you a link that has all the answers to Chimney related questions. It will definitely help you know what really is causing smoke and how to resolve it.