I currently have -1 on my endurance from barrel cactus fruit, however, I haven't eaten any in a long time. And what I have eaten has worn off. It seems that this effect is stuck. I am on a 360 so I can't go into the console and remove anything. Has anyone else experience anything like this? Maybe its something else that I've not noticed, I don't know. If I remember correctly it seemed like Oblivion had similar issues where certain stats/attributes would be in red for no apparent reason.

Bueller?

Does it say it's from the fruit under EFF?
If so, don't be so sure it's worn off yet. Those negative stats often last longer than you expect.

Have you tried removing your addictions? Its only a suggestion, but it might work.

Also make sure you're not suffering from RAD sickness.