June 8, 2026, 11:08 am | Read time: 5 minutes
From a distance, it’s hardly noticeable. But the closer you get, the more clearly you can see the white foam around the horse’s mouth. This foamy beard is especially common during riding or training. Many riders see it as a sign of relaxation and contentment. But is that really true? PETBOOK investigates the myth.
Is Foam Actually a Good Sign?
For a long time, it was believed that foam at a horse’s mouth, especially while riding, was a good sign. In equestrian terms, this is referred to as “chewing” or “mouthing.” This involves a chewing-like mouth activity that triggers a lot of saliva production in the horse. Normally, this happens mainly while eating: Due to the high fiber content in their diet, saliva production aids in better digestibility. The grass or hay is mixed with saliva while chewing, making it easier to transport as a food bolus to the stomach. Since horses are prey animals, producing a lot of saliva while eating is considered a particular sign of relaxation.1
However, increased mouth activity does not occur exclusively in relaxed situations. Many horses also begin to chew more on the bit during physical exertion or under stress. The amount of saliva produced depends, among other things, on the bit used, its material, and the intensity of the chewing movements. Additionally, horses react very differently: While some animals foam noticeably with slight mouth activity, others show hardly any visible saliva flow. Therefore, foam at the mouth alone is not a reliable indicator of whether a horse is relaxed.
How Can I Tell if My Horse Is Relaxed While Riding?
If you want to know whether a horse is relaxed while riding, you should pay less attention to the foam at the mouth and more to the overall body language. Only the combination of various signals reveals whether the animal truly feels comfortable and moves freely.
Typical signs of a relaxed horse while riding include:
- a loosely carried neck without visible tension
- calm, even movements
- swinging back
- a calm facial expression
- relaxed mouth area
- regular snorting
Only when several of these characteristics come together can foam at the mouth be considered part of a positive overall picture. Therefore, foam at the horse’s mouth is not a reliable proof of relaxation, but merely a possible side effect of active saliva production.
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When Excessive Saliva Flow Can Indicate a Disease
Horses produce between five and ten liters of saliva daily for their digestion. Therefore, it’s completely normal for foam to form at the mouth while eating. This effect is often observed, especially with juicy food or treats like apples. So, excessive saliva flow is not automatically a cause for concern.
In some cases, however, unusually high saliva production can indicate health problems. One possible cause is the so-called slobber syndrome. This results in excessive saliva flow triggered by the toxin slaframine. This toxin is produced by the fungus “Rhizoctonia leguminicola,” which primarily affects alfalfa and red and white clover. The affected plants often have black or brown spots, which is why the disease is also known as “black patch disease.” 2
Primarily, affected animals show the typical excessive saliva flow, but also increased tear flow and urination. In most cases, the symptoms disappear once horses no longer eat the affected plants. Nevertheless, horse owners should always consult a veterinarian if there is noticeably excessive saliva flow.
However, excessive saliva flow doesn’t always have to be caused by fungal toxins. Dental problems, mouth injuries, or poorly fitting equipment can also increase saliva production.
Why Artificial Foam Has Been Banned at Competitions Since 2025
The extent to which foam at the mouth still occupies the equestrian world was evident in 2025. For decades, a foaming horse was considered by many riders and judges as a sign of relaxation and good bit acceptance. Accordingly, there was a strong desire to convey this impression at competitions as well.
It had already been documented several times that some riders used aids to artificially create foam at the horse’s mouth. The so-called “Marshmallow Fluff” became particularly well-known–a white, foamy sugar paste applied around the mouth to give the impression of an intensely chewing horse. Reports suggest that similar products were even used at high-class international competitions.3
To put a stop to such practices, the International Equestrian Federation (FEI) decided on a rule change. Since July 1, 2025, all products that can imitate, induce, or enhance foam at the horse’s mouth are banned at FEI competitions. Products that coat or partially cover the bit are also no longer allowed.4
The discussion about artificially created foam shows the significance still attributed to the white foamy beard in equestrian sports. In reality, foam at the mouth is primarily one thing: a sign of saliva production. Whether a horse is relaxed, healthy, and content can only be determined by looking at the whole animal–not just the white foam around its mouth.