Actually depends on what your ceiling is made of. For regular textured ceilings, I would use some diluted Simple Green. I've used it on my ceiling from where I swatted a fly and it worked super. If you have a popcorn texture ceiling, there isn't much you can do. Otherwise, try some Simple Green! That stuff is great!
Ask a Pastafarian.
If it is a popcorn ceiling just spray it with some kind of disinfectant and then repaint.