How Much Penicillin Can You Give a Horse?

Last Updated on April 8, 2020 by Charlie

Have you ever used Penicillin for an infection or on a cut? Did you know that you can also use Penicillin for your horse? As with all veterinary matters, always defer to your vet’s judgment, but it is safe to use Penicillin on horses, as long as it is done in the right ways and in the right amounts! How much penicillin to give a horse?

Penicillin can be used on many animals to help with many different things.  In this article, I’ll be discussing what Penicillin does, who can use it, how you give a horse Penicillin, and most importantly, how much Penicillin it is safe to give a horse.

What is the Purpose of Penicillin?
How Much Penicillin Can You Give a ...
How Much Penicillin Can You Give a Horse?

Maybe you’ve heard the word Penicillin before; perhaps you have some sitting in your medicine cabinet at home.  But do you know what Penicillin does, or what it is?

Penicillin is a bactericide that is used to treat infections.  Its primary function is to enter into infected areas of skin and flesh and to kill bacteria in these areas.  These infected areas should be observed by a vet before Penicillin is used, but frequently vets will recommend its use.


Who is Penicillin for?

Penicillin is can be used for many animals and even people.  But there are different types of Penicillin for different types of organisms.  In this case, Penicillin G Procaine is intended to be used to treat horses, cows, pigs, and sheep.

There are also different types of Penicillin, administered in different ways, that are suitable for people, cats, dogs, and other animals.  Penicillin is used to treat different types of infections in all branches of life that it extends to.

As stated, different types of Penicillin are appropriate for different kinds of animals.  Similarly, different types of Penicillin have different forms of consumption. For example, for humans, Penicillin can take the form of a tablet or liquid medicine.

For horses, Penicillin is an injectable form administered with a syringe.  If you are not familiar with using a syringe, and your vet has determined that Penicillin is needed to treat your horse, please have it demonstrated before trying on your own.  Incorrect use of a syringe can severely injure yourself or the horse.

How Do You Give A Horse Penicillin?

The syringe should have a 16 or 18 gauge needle, at approximately 1.5 inches long.  It should be disinfected and cleaned before use to prevent further infection. They should also be sterilized before use.

The syringe should be injected in the muscular areas of the horse near his hips, hind end, upper legs, or neck.  A syringe should NOT be injected into a blood vessel or near a major nerve or nerve area. If the injected area begins bleeding while the syringe is inserted, remove and restart immediately.

If your horse is being treated with Penicillin for multiple days, each injection should be done in a different location or his body; injections should never be done in the same place during the same injection period.

If you are unsure of how your horse will react to injections, or you know for a fact your horse misbehaves when injected, have someone present to help prevent your horse from moving, which could cause injury both to himself and those present.

How Much Penicillin Should You Give a Horse?

Finally, how much Penicillin is it safe to give your horse? Assume your vet prescribes your horse Penicillin for an infected area, and you safely know how to administer an injection via syringe.  Now what?

Horses can get 1.0 mL of Penicillin for every 100 pounds of body weight, once a day.  So, if your horse weighs approximately 1,000 pounds, he could get 10.0mL of Penicillin daily.  Typically, the exact dosage will be disclosed to you by your vet, because it will depend on the circumstances.

If your vet does recommend the 1.0mL for every 100 pounds method for determining a  correct dosage, then the dosage will obviously depend on how large and heavy your horse is! For example, you wouldn’t be using the same dosage on a mini horse as you would on a Clydesdale.  

How Much Penicillin Should You Give a Horse?

Your vet should be able to make a safe guess as to how much your horse weighs by simply looking at him, but it never hurts to have your horse professionally weighed from time to time, for scenarios just like this.

Duration of the dosages will also depend on the circumstances; how severe the infection is, how long it has been around, the horse’s overall health, etc.  

Penicillin For Horse

Sometimes horses only need to be injected with Penicillin one time, sometimes they need to be injected with Penicillin every day for a week, and sometimes they need to be injected with Penicillin every day for a month- it all depends on each horse’s individual situation.

Your vet will be able to recommend what correct duration for your horse’s treatment will be.  In some cases, there will be a prescribed duration before a revisit; the revisit will tell whether that duration needs to be extended, or whether the horse has healed enough to be taken off the Penicillin.


Penicillin has many uses for many different creatures, both human and animal! It is extremely effective in treating bacterial infections in horses, though one must be careful and seek out veterinary advice before using it on horses.

Penicillin on horses can be given up to 1.0mL per every 100 pounds a horse weighs. This will depend on the size and density of each individual horse! Make sure you know how to safely administer and use Penicillin before using it on your horse.

I hope this article helped you better understand how Penicillin can be safely used to treat horses and how much Penicillin is safe to use on a horse! If so, please share this article, and share with us your stories of using Penicillin on horses!