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


Foal Over 1 Week Old has Diarrhea


Diarrhea in foals more than 1 week old can be a serious life-threatening problem, but often is not.

"Foal heat diarrhea" is a "normal" diarrhea that occurs in most foals between 1-2 weeks of age and is thought to be caused by dietary changes. Sand accumulation in the growing foal is also fairly common and can cause chronic diarrhea. Bacterial infections can also cause diarrhea, are life-threatening and require prompt treatment. There are many other less common causes including intestinal parasites.

A foal with "foal heat diarrhea" will continue to appear bright, nurse and be active. A foal with diarrhea that appears depressed, has stopped nursing or is lethargic must be seen immediately by a vet.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
    • If the foal is not as bright as normal or not nursing normally.
  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • If the foal appears otherwise normal, i.e. is active and nursing normally.
    • If the diarrhea lasts longer than a few days or occurs in a foal over 2 weeks of age.

your role


What To Do

Watch your foal's attitude and appetite carefully. Look at your foal's gums and assess their refill time, they should be light pink and refill should be 1-2 seconds. Consider whether other foals are affected. Report your findings and concerns to your vet.

If the foal appears even slightly depressed or dull, your vet should promptly perform a physical examination and laboratory work to determine the nature of the diarrhea.

Talk to your vet about providing symptomatic treatments such as Pepto Bismol (Bismuth subsalicylate), smegtite (Biosponge), or probiotics (which may be more effective in foals than in adults). Applying vaseline or similar skin protectant under the tail and down the legs can reduce skin scalding from diarrhea.

What Not To Do

Do not assume that diarrhea in the growing foal is benign. It can be life-threatening. The key is monitoring attitude and communicating with your vet.

your vet's role

There are a handful of common causes of growing foal diarrhea. We rule out problems that need to be treated. The number of diagnostics performed is usually related to whether or not the foal seems sick from the condition causing the diarrhea, and the severity of the diarrhea.
Questions Your Vet Might Ask:
  • What are the results of the Whole Horse Exam (WHE)?
  • How is the foal's attitude and appetite?
  • Does your foal seem normal otherwise?
  • How old is the foal?
  • When did you first notice this?
  • To your knowledge, das the foal consumed sand?
  • Is the foal showing any signs of abdominal pain (colic)?
  • Is the foal straining to defecate now or was it earlier?
  • Was the foal examined after birth by a veterinarian?
  • What is your parasite control program?

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

further reading & resources

Author: Doug Thal DVM Dipl. ABVP