What you see. The starting point for addressing any equine health related issue is your observation.


Membranes of Mouth, Gums appear Red


There are a few areas on the body that provide important information regarding the state of a horse's circulatory health. These areas include the gums, the pink membrane inside the nostril, the whites of the eyes, and the pink inner vulvar membranes of mares. The simple act of evaluating the color of your horse's gums is actually a very important skill.

If instead of a healthy pink color, the gums are a dark red, "endotoxemia" is the presumed cause. Endotoxemia is a condition in which endotoxin from intestinal bacteria has entered the circulatory system, usually because of intestinal inflammation or damage. Endotoxin is a potent toxin that is part of the intestinal bacterial cell wall. Other toxins and conditions can also cause this appearance to the gums.

A dark red color of the gums usually indicates that a horse is suffering from a serious illness. You would expect to see other signs along with this, like high heart rate and slow refill time, and generally a depressed horse. If this finding is "real", then you would expect the horse to also be exhibiting other signs of illness.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
    • If the results of the Whole Horse Exam (WHE) in the resting horse indicate fever (Temp >101F/38.3C) or heart rate greater than 48 BPM.
  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the horse seems to be moving freely, and has a normal appetite and attitude.
    • If the results of the Whole Horse Exam (WHE) suggest the horse is otherwise normal.

your role


What To Do

It is easy to misread gum color. Reexamine your horse's gums in different light. Always check both sides of the mouth if you think your horse's gums are a strange color. Wipe the gums clean with a moist paper towel. There may be material on the gums that is confusing your interpretation. Inflammation of the gums (gingivitis) can also impart a red color to the gums, usually along the tooth margin.

When in doubt, assess your horse's general health using the Whole Horse Exam (WHE), paying particular attention to capillary refill rate and heart rate. Look for other signs of illness or disease. Call your vet to discuss your concerns.

your vet's role

Your vet may advise you to take a "wait and see" approach or suggest that they examine your horse. Much of this will depend on history and the presence or absence of other concerning signs. They will likely assess your horse's general health with a physical examination, and try to determine the nature of the finding. Blood work may provide additional important information.
Questions Your Vet Might Ask:
  • When did you first notice this problem?
  • Have you given the horse any medications, vaccinations or dewormers lately?
  • Have you changed your horse's feed or management lately?
  • Have you noticed that the horse has had diarrhea?
  • What does the horse's manure look like?
  • Has the horse eaten any extra grain recently?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
more diagnoses

Author: Doug Thal DVM Dipl. ABVP