What does it mean when my cat's body starts twitching? I'm fairly positive it's not fleas because she's never been outside of my apartment and there are no other animals near here. My boyfriend said that it could be hairballs, even though that's not the conclusion I would derive just from watching her.. She doesn't appear to be close to coughing things up. What could be causing her whole body to twitch? What can I do to help?