Have a medical condition or running-related injury that somehow cleared up when ditching the shoes? Please share!

For me, running barefoot got rid of persistent shin splints as well as knee and back pain.

However, because I didn't have a mentor when I started 11 years ago, I developed large bone spurs at the backs of both of my heels.  I didn't figure out the form problem until I was into this 8 1/2 years!  I'm a really slow learner!  That's why I stress stress stress proper running form!  I learned the hard way to land midfoot and NOT on the toes.  Landing on the heels is painful so that was a no brainer, but landing on my toes didn't hurt, at first, and when it did 8.5 years later, it was way too late then.  The good thing is that the surgery to remove the bone spurs should restore my ability to run farther and faster again and I don't anticipate the spurs will return.

Did you highlight/copy then paste, Wendy?

 My original reason to try flat shoes was help with chronic knee soreness, I could never make it a whole summer before I had to stop with hurting knee's usually both...knee's have good ever since.  My bad ankles got worse at first until I started barefoot running then slowly improved although I doubt they will ever be 100% due to a long history of sprains which I part way blame on over thick shoes. It may or may not be related but my back hasn't bothered me since I started barefoot running either...I had been going to a chiropractor regular for a couple years before that. 

This isn't a barefoot-related cure, but Mr Deplume switched to his old Nike Frees a couple of months ago (he had started to run in them 3 years ago, btu then listened to the "Experts" and switched to big fluffy shoes). A couple of hundred miles of wearing them and his hammer toes are remarkably less hammer-y. I noticed it one day when he was standing barefoot in the kitchen, and though to myself, "gee, his toes look flatter than I remember them." (which is saying a lot: the guy had seriously ugly gnarled tree-stump-like feet for the whole time I've known him). I didn't say anything to him because I thought maybe I had just imagined a change.

Then this weekend, after having finished reading 'Born To Run', he pulled off his socks and really looked at his feet. He walked over to me and showed them to me. After talking about it, we're both pretty gobsmacked at the change. If we had known that going to a reduced shoe might make a difference in the structure of his feet, we would have taken "before" pictures.

Also, the fact that he's been training for a half marathon May 1 and has no toenail bruises is a miracle in itself. Even though the Free's aren't exactly minimal, they are a world away from the giant motion control shoes that the running store said he needed. And that made him lose a toenail every training cycle.

 I had lower back issues that gradually worsened until I was walking with a cane.  Last spring, I found an article that said raised heels were bad for your posture and I switched to minimal footwear (VFF KSOs).  The improvement was so dramatic I put away the cane, started to run, did the Couch to 5K program, and now dream of someday running an ultra.  Full story here.