Thrush in Horses – Causes, Symptoms and Treatments

If you’ve been in the horse industry long enough there is a good chance you’ve encountered thrush in varying degrees. It really is one of those horse ailments that when your horse has it, you know. But in case you’re worried you’ll miss the disgusting odor and pus oozing hoof, here is some key information to help you diagnose, treat and prevent thrush in horses.

What is thrush?

Thrush is an infection in the horse’s frog, specifically thrush affects the central and lateral sulcus of the frog.
Diagram of horse hoof

What causes thrush in horses?

Thrush is usually a bacterial infection but can occasionally be a fungal one. Thrush occurs when the organism, Spherophorus neaophorus, makes it’s way into the horse’s frog and eats away at the tissue. Dirty and damp stable conditions make for the perfect environment for this organism, horses that are confined to manure and urine soak ground are the best candidates for thrush.

Thrush symptoms

The symptom that is usually noticed first is the horrid odor of rotting flesh when you pick up your horse’s hoof. It really is that bad. The second sign is a black liquid oozing from the frog, this is a result of the organism eating the frog tissue. In most cases your horse will not any exhibit any discomfort.
The image below does a good job showing what thrush looks like. You can see the healthy hoof on the left with a clean, easily visible frog. The infected hoof on the right has a dark discharge coming out of it and the frog is pealing.
Thrush in horses

How to treat thrush in horses

Mild cases of thrush can be easily treated with proper maintenance and topical medicines. It’s imperative to not only clean your horses hoof, but keep his area clean and dry.
First you want to get out as much dirt and grime out of the hoof as possible. Be careful when cleaning the hoof not to pick off too much of the deteriorated frog. Also you don’t want to drown the hoof in ointments, this could just lock in moisture and not actually kill the bacteria.
Next wrap cotton around the end of the hoof pick. Dip the hoof pick into a solution and gently swap the sides of the frog. Make sure to get into the crevices where bacteria could be hiding. I generally use a terpentine solution but others have used bleach, depends on preference.
Once the frog is cleaned out, applying a thrush ointment will help speed up the healing process as well as prevent further infection. My go to is Thrush Buster . It easy to apply and the unique coloring ensures that you get the liquid into the desired areas of the hoof – just don’t get on anything else, it stains horribly. No Thrush Dry Formula is neater choice. It’s a dry powder thats all natural, plus you can use it on rain or scratches too! For a household fix, apple cider vinegar works. Most recommend filling a bucket and soaking the hoof in it for 15 mins. for at least 3 days. I find it easier to fill a spray bottle and just spray the hoof a few times a day until thrush is gone.
P.S. Smartpak Equine has a ton of options to choose from.  Click here to save some money on your new thrush supplies!

Preventing thrush

The best prevention is a clean, dry stall but even then some horses will still contract it. Daily cleaning of the hoof and application of a thrush ointment goes a long way. Also try to avoid sharing hoof picks throughout the barn, that’s just asking for trouble.


Can thrush make a horse lame?

In most cases it does not cause lameness. Your horse may not show any signs of discomfort whatsoever. Prolong, untreated cases of thrush can affect the sensitive parts of the frog leading to soreness and other potential ailments.

Can people get thrush from horses?

People cannot contract thrush from horses. Thrush in humans is generally caused by a yeast called Candida, different than the organism that causes it in horses.


Fortunately, thrush in horses is usually a simple thing to fix and prevent. If you find your horse contracts thrush frequently look into other shoeing options. Farriers can usually reshape the hoof to give the frog less contact with the ground or fix the slope of the heel. Also try changing the bedding, wood pellets are known to absorb water instantly, perfect for a thrushy horse!