Cinnamon anyone?!
In my travels doing equine dentistry I hear a lot of interesting things. And from time to time come across a remedy or recipe for a cure that is working. Many times these solutions are simple, and have been around for a long time.
This is one of those!
Use a teaspoon of cinnamon, morning and night, in the feed of a horse who has chronic diarrhea.
This is apparently an old European remedy. I have run into several different people who have used this to good effect. It is simple and inexpensive and does not have a down side. And it seems to work!