$ sudo apt-get remove libtheora0 

Uninstall libtheora0 including dependent package

If you would like to remove libtheora0 and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove libtheora0 

Use Purging libtheora0

If you use with purge options to libtheora0 package all the configuration and dependent packages will be removed.

$ sudo apt-get purge libtheora0 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove libtheora0 

See Also,