According to information shared with us by the author of The Healthy Pet Herb Guide,

...horses respond wonderfully to LIV-C (Chinese Liver Balance) and/or Dandelion. If a horse is having problems with the urinary system, Dandelion together with KB-C would be the best.

If a horse is having reoccurring stone problems, then the horse's body is to acidic - sometimes caused by a diet that is too high in protein. Check the grain, supplements, etc. that is being fed to the horse and check the protein levels.

To bring an acidic horse back to more normal ranges, I have used SynerPro Calcium-Magnesium quite successfully. Check the horse's urine with the pH test strips.

To order a copy of The Healthy Pet Herb Guide, click on the link below:

http://herballure.com/Products/HealthyPetHerbGuide/index.html