Diarrhea vs FWS

Diarrhea vs FWS (Fecal Water Syndrome)

 As this comes up on a regular basis, I have decided to do a side by side of these two issues, though not in extremely technical terms as there are many very good articles on the internet that addresses the technicalities of each. My approach will be on distinguishing the difference and how to treat both. Neither is a pleasant issue to address but as horse people, we know that paying attention to our horse’s poo can tell us a lot about their current health. While we have had many horses we have helped with FWS, our mini gelding Cisco has so far been the most challenging with this issue, mostly due to his age (20 when he came to us)


The Difference in Appearance:

Diarrhea is defined as loose stool. It does not hold its form. It can be anywhere from being all one poo (not formed into individual balls) to complete liquid. In most cases this is from some type of irritation to the digestive track that once removed, quickly resolves itself. The most common reason that I see for diarrhea is over fertilized very green hay. The high nitrate level of over fertilized hay causes irritation in the digestive tract that speeds up digestion so the food does not have time to break down properly. You will often see pieces of undigested hay in the poo when this happens (but not always) It also shows a lack of protective mucous in the digestive tract and often leads to ulcers. These horses are also often high anxiety and that anxiety level adds to digestive issues. So when dealing with diarrhea, reduce stress, change the diet, and the issues will resolve quickly. (more below)

FWS (Fecal Water Syndrome) is often triggered the same way (food and stress) with added damage to the digestive tract so that when liquid is normally absorbed in the digestive tract is not absorbed. Even though the stool may be formed as it should (into small individual balls) it also passes with a lot of water that should have been absorbed in the intestines but was not. Of the two, FWS is harder to heal, takes longer and is something that generally has to be kept up for the life of the horse. Sometimes the two are combined and even if a horse with FWS is “healed” it can often have boughts of diarhhea with feed changes.


Methods of Healing:

  • For both issues, a change of diet is a MUST.
  • Avoid added chemicals (this includes chemical dewormers),
  • Reduce stress
  • Build a diet that focuses on repair of the digestive tract. Low sugar, high fiber, and healthy fats are all important for the basic diet to repair FWS.
  • Most “complete feeds” contain chemicals that will make the issue worse so they should be avoided. Single ingredient feeds and creating your own diet for your horse is preferred so you are able to build a more “whole foods” diet and avoid “probiotics” which should not be given daily as they can lead to candida overload, which can lead to chronic diarrhea. Avoid feeds that include: Beet Pulp, Wheat and Soy.
  • “Natural” hays should be chosen over super green over fertilized hays.
  • Adding digestion supporting herbs (like those in our Tummy B Calm blends) are necessary for healing of the digestive tract. In nature, horses seek out these herbs not for repair, but for support when they are available in their territory.
  • Expect healing to take TIME! While diarrhea is in most cases a “quicker” fix, it still may take months (and rarely but it can happen, take 1 to 2 years) to completely heal the digestive tract. Part of this is because there is no such thing as perfectly clean feed or environment but we can only do the best we can and give the process time to happen.
  • WATER: Clean water is VERY important and should not be overlooked as part of the healing process. We found that putting even just a carbon filter on the watering hose makes a difference. However, some people may need bigger filtering systems and should have their water tested. We found our water had high lead, which is easy to remove most of with a carbon filter but if the water is bad for your horse, remember it is bad for you too!


FWS is a much more involved and healing time is going to take much longer and most likely be a life time issue. Certain herbs should be avoided with FWS (or given very controlled amounts). Some of those items are: Cayenne, MSM, Kelp, Ginger to name a few…especially in the beginning stages of healing they may “excite” the digestive tract too much and delay healing. I am still testing our mini, Cisco, to see what triggers him to start having FWS issues after over a year of being on our diet plan and supporting herbs. As it tends to be “collective” he is able to have small amounts of some of those items (MSM and Kelp) but if, say, he is given hay that is too strong, he can only handle a very tiny amount of those herbs if any at all. We had to purchase some hay that was far too strong for him for a short time and he went back to having issues, but as soon as I replaced that hay with a milder hay, he soon went back to having normal poos and I can re-introduce the MSM and Kelp he is normally on (at small dosages). Cisco is also allowed to graze so throughout the year I am checking to see if seasonal grasses will make his issues worse (or not) with the current herbs he is on.

There are many natural items on the market that may help with symptoms of FWS (and diarrhea) but most of them will not add to healing or are a very minor help to healing. Those items are:

Redmond Daily Gold

Aloe Vera

Psyllium (by itself)

Alfalfa (can be useful with ulcers but is usually too over fertilized and makes FWS and Diarrhea worse in most cases)

Diatomaceous Earth

Probiotics (preferably “natural” probiotics, such as Organic Apple Cider Vinegar, Plain Kefir, Kombucha (its easy to make home made!) etc rather than chemically produced probiotics.

Herbs that are necessary for healing are those that increase the mucous lining of the digestive tract like in our Tummy B Calm Blends:

Slippery Elm


Marshmallow Root


Supporting Diet:

The supporting diet for both Diarrhea and FWS syndrome must be free of irritants and things that cause inflammation and destroy the mucous lining. Unfortunately, MOST commercial “complete” feeds cause irritation and inflammation. Check out our diet page for ideas on how to feed to support a healthy digestive tract.


Chances are for most horses with chronic diarrhea and FWS it will be a lifelong control of diet in order to control symptoms as there has been some type of damage that cannot be completely healed. I recently spoke to a customer who’s neighbor sprayed the fence line with an herbicide and the horse ate enough of the grass with herbicide on it to damage the horse’s digestive tract. The horse has been on our diet and herbs for about two months at the time of the article, and is showing very good response. The owner says the horse is not only showing physical improvements but mental improvements as well as the horse is going through healing and is feeling less pain and digestive stress. It just goes to show how physical issues not only effect the body, but the mind as well. I have with every customer that says they have a horse that is “out of control”, “highly stressed” etc asked them what is wrong with them physically. Often they say “nothing” but if they are willing to think outside the box and go through the process with me, we often find there are digestive, hormonal and pain issues that were hidden under all the obvious mental issues. Which one started first? Hard to tell since in most of these cases the horse is fairly new to the owner (or it’s a person fairly new to horses) and they just don’t have enough background information to go by in order to help that horse on their own. Quite often its very important to find someone who is on the outside looking in that can come up with new ideas and new things to look for.



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1 comment
  • Thanks for writing this. I just wrote you about my sensitive mare – trying calmer now on her. However, I also have a 10 yo gelding that is IR with FWS. He is on a very specialized diet (analyzed teff hay, which is supplemented accordingly). His condition has been handled well with annual short courses of psyllium. However, that is not longer effective. So, I am hoping to discuss with you a plan of attack.
    Jeannette McCarroll
    760-449-8990 California

    Jeannette McCarroll on

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