Thanks for the replies, all.

I'm only 26 and experienced horrible stomach cramping after the 15K I did in November. I attributed that to being dehydrated and getting over being sick.

I never seem to have a run where I don't experience even acute stomach pain, so I figured that was sort of the way it goes with running and me. I was really hoping to do a half marathon. I know my legs would do fine, but I'm pretty sure the stomach pain (followed by the stomach purge) would really keep me under water.

It was definitely vaginal bleeding. A tampon took care of it.

I stayed away from running yesterday and instead did 30 minutes on the elliptical. I thought maybe the stomach problems had to do with my erratic breathing when I run (I never have these problems when I ride), so I wanted to do something to really get my heartrate up without running. I got on the stairmaster and cranked it up to level 20 - 10.1 floors a minute. I was sweating profusely and my heart was pounding. I felt fine after that 1 hour workout.

I didn't have any problems for the rest of the night. The cramping was mostly gone. No bowel movements. I had a turkey burger wrapped in lettuce for dinner. Handled that well.

My only conclusion is that it has to do with the impact of running. Has anyone heard of the dairy colostrum supplement that runners are using for this issue? Is it just a fallacy? Would going to a sports' doctor (is there such a thing) help pinpoint the issue? I don't seem to have a problem with wheat/gluten otherwise - these bouts seem only to be spurred after running. I have regular BMs, nothing weird, scary, out of line, etc. I eat a lot of "roughage", fruit. I try to avoid those things if I know I'm going to run because I thought maybe it's too much fiber for my stomach to handle.

As you can tell through my rambling, I've tried many different things and this problem is just so darned persistent.

Again, very appreciate of the feedback. One day at a time, I guess.