I have a 26 year old TWH that has chronic diarrhea. He had vet work done last year, when it first started, with his blood work coming back normal, fecal exam okay and teeth are okay. No feed or hay change. Actually, his stool will be somewhat normal, not firm apples but has some substance to them, for most of the time then about once or twice a month it gets loose to the point of liquid. I had him on ProBalance during some of this time period but it did not seem to affect his stool. He is now on Stomach Smoother but still having the same results as with ProBalance. His coat is shiny, he eats all his grain and most of his coastal hay (his preferred hay for 23 years) and is still very active. His weight is pretty much staying the same the last year. GB

Dear GB,

I have received a rash of questions about diarrhea this week. The answer is pretty much the same for all of them. (Aren’t you glad I didn’t include a picture with this entry?)

Diarrhea is one of those conditions that differs from horse to horse. Because what works for one doesn’t always work for another, you just have to start somewhere, keep a good journal, and try different treatments until something works.

You’ve started in the right place: with your veterinarian. That is, ruling out some of the more common causes through a complete physical examination, blood work and fecal exam. Some uncommon causes of chronic diarrhea require particular tests of blood, feces and even GI tissues; you may have to specifically ask your vet to run these additional tests.

When experimenting with treatments, I recommend keeping a record of everything you try and sharing this “diarrhea diary” with your vet. Before you try anything though, I strongly encourage you to deworm your horse (no matter the result of the fecal) with Panacur PowerPac (if he’s not debilitated). Then give a product with ivermectin and praziquantel to ensure complete coverage of all internal worm species.

Next either try adding products to his diet or changing his diet, but not both at the same time, because then you won’t know which treatment worked! Since your horse has been eating coastal hay, you could switch him to another kind of grass hay or to alfalfa hay. You could also try changing his grain or replacing it altogether with a multi-vitamin/mineral supplement or ration balancer. Remember to make any diet changes slowly, over a two-week period, so your horse doesn’t develop additional problems like colic or laminitis.

Here is a list of products to try to see if they help. Give them one at a time, with your vet’s advice, and for at least 30 days:

• Probiotics, prebiotics, or yeast – to reinoculate and feed the “good bugs”
• Kaopectate and Pepto-Bismol – coat, soothe, relieve!
• Psyllium – in case the diarrhea is caused by inflammation from sand
• Daily dewormer – to prevent gut wall damage from parasites
• Natural anti-inflammatories – MSM or DMG are good choices to quiet a gut
• Digestive enzymes – like those found in Ultra-Elite Digest or Digest-It
• Hindgut buffer – for example EquiShure
• Digestive support – products with L-glutamine, Licorice, Oat fiber and oil
• Plant extracts – like those in APF, to normalize the body’s systems

If none of these over-the-counter treatments work, you may have to go back to your vet and start trying prescription products. Here are a few that have worked for some horses:

• Rheaform – a prescription product that reduces motility in the colon
• Opiates – prescription narcotics related to morphine
• Steroids – prescription immune suppressants
• Antihistamines – prescription products that may work best with steroids
• Antibiotics – prescription only since some antibiotics can worsen the situation!
• Lomotil - prescription anti-diarrhea medication
• Imodium – over-the-counter anti-diarrhea medication

Unfortunately, it’s not uncommon for a treatment to work for a few weeks or months then the horse’s stool gets sloppy again. And some horses never improve, struggling with chronic diarrhea the rest of their lives. Just be patient and thorough and hope for the best!