Strangles treatment centers on supportive care, isolation, and monitoring for complications. Most horses recover on their own within a few weeks once abscesses in the lymph nodes rupture and drain, but the disease is highly contagious and can turn serious if infection spreads beyond the throat. Your veterinarian’s role is critical from the start, both for the sick horse and for protecting the rest of the herd.
What Strangles Does to Your Horse
Strangles is a bacterial infection caused by Streptococcus equi that targets the lymph nodes around the jaw and throat. The hallmark signs are a high fever (often 103°F or higher), thick nasal discharge, and swollen lymph nodes that eventually form abscesses. Those abscesses put pressure on the airway and make swallowing painful, which is where the name “strangles” comes from.
In a straightforward case, the abscesses mature over roughly one to two weeks, rupture on their own, drain, and the horse starts feeling better. The entire course from first fever to resolution typically runs three to four weeks. Complications arise when the infection doesn’t stay contained to those lymph nodes, a situation called “bastard strangles,” or when pus accumulates in the guttural pouches (air-filled cavities behind the skull connected to the ears and throat).
Supportive Care at Home
The backbone of treatment for an uncomplicated case is keeping the horse comfortable while the infection runs its course. That means rest, soft food (since swollen lymph nodes make chewing and swallowing difficult), and easy access to fresh water. Soaked hay, bran mashes, or pelleted feed softened with water all go down easier than dry hay or grain.
Anti-inflammatory medications help reduce fever and throat pain, making the horse more willing to eat and drink. Your vet will guide the specific medication and dose based on your horse’s weight and condition. Keeping the horse hydrated is especially important because fever and reduced water intake can compound each other quickly.
Warm compresses applied to swollen lymph nodes can help abscesses mature and rupture faster. Once an abscess opens, flushing the site with a dilute antiseptic solution and keeping the area clean speeds healing and reduces the chance of reinfection. Some vets will lance an abscess that’s clearly ready to drain but hasn’t opened on its own.
When Antibiotics Are Used
This is where strangles treatment gets counterintuitive. Antibiotics can kill the bacteria, but giving them at the wrong stage can actually cause problems. If you start antibiotics after abscesses have already begun forming, the drugs may partially suppress the infection without clearing it, leaving the horse with poorly drained abscesses and a weaker immune response. That horse is then more likely to become a long-term carrier or develop complications.
Antibiotics make the most sense in two scenarios. The first is very early in the disease, before abscesses form, when a horse has a fever and nasal discharge but no lymph node swelling yet. At that stage, antibiotics can sometimes stop the infection in its tracks. The second scenario is a horse that develops serious complications: the infection has spread to other parts of the body, the horse can barely breathe due to airway compression, or the animal is severely debilitated.
Penicillin is the standard antibiotic for strangles. The labeled dose for horses is 3,000 units per pound of body weight, given daily by intramuscular injection. Treatment typically continues until symptoms resolve, usually two to three days, and for at least one day after symptoms disappear. Your vet will determine whether your horse actually needs antibiotics, because in many cases the better strategy is to let the abscesses develop, drain, and resolve naturally.
Guttural Pouch Complications
About 10% of horses that recover from strangles retain infection in one or both guttural pouches. Pus collects in these pouches and, because the inflammation disrupts the normal clearing mechanisms, the horse can’t drain it on its own. Over time, that trapped pus dries out and hardens into stone-like masses called chondroids. A horse carrying chondroids may look completely healthy but continue shedding bacteria for months or even years, silently reinfecting other horses.
Diagnosis requires endoscopy, where a small camera is passed through the nostril into the guttural pouch. If chondroids are present, they generally have to be flushed out or removed manually, sometimes requiring surgery. No chemical agents have been found that safely dissolve them. Compounds that have been tried tend to cause severe trauma to the pouch lining. This is one reason post-recovery testing matters so much: you need to confirm the horse has actually cleared the infection, not just stopped showing symptoms.
Quarantine and Biosecurity
Strangles spreads through nasal discharge, shared water troughs, feed buckets, grooming tools, and even your hands and clothing. The moment you suspect strangles, isolate the affected horse. A quarantine distance of at least 30 feet from other horses is a common recommendation, with dedicated equipment, boots, and clothing for handling the sick animal.
New horses on the property and any that had direct or indirect contact with the sick horse should have their temperatures taken twice daily. A fever is often the first sign, appearing before nasal discharge or swelling, so catching it early lets you isolate a newly infected horse before it becomes maximally contagious.
The quarantine period doesn’t end when symptoms resolve. Horses can shed bacteria for weeks after they look and feel normal. Cornell University’s veterinary diagnostic lab recommends three consecutive negative guttural pouch washes, collected seven days apart over a 21-day period, to confirm a horse is no longer shedding. Only after those three negative results should you consider reintroducing the horse to the herd. Skipping this step is how outbreaks restart.
Vaccination Options
Two types of strangles vaccines are available, and neither provides bulletproof protection. The killed (injectable) vaccine requires a primary series of three doses given three weeks apart, followed by annual boosters. Studies show it reduces the clinical attack rate by only about 50%, meaning vaccinated horses can still get strangles, though often with milder symptoms.
The modified live vaccine is given intranasally (squirted into the nostril) as a two-dose primary series, with doses spaced two to three weeks apart, followed by annual revaccination. This version stimulates a stronger immune response than the injectable form because it mimics natural infection at the mucosal surface where the bacteria first take hold.
Vaccination is most useful on farms with a history of strangles or where horses frequently move in and out, like boarding barns, training facilities, and show grounds. It’s not typically recommended for every horse in every situation. One important caution: vaccinating a horse that’s currently infected or was recently exposed can worsen the disease. Your vet can help you decide whether vaccination fits your herd’s risk profile and timing.
What Recovery Looks Like
Most horses recover fully from strangles and develop strong natural immunity that lasts roughly five years, though it’s not absolute. During recovery, expect the horse to be off work for several weeks. Appetite and energy return gradually after abscesses drain. The lymph node sites may leave small scars but rarely cause long-term problems.
The horses to watch most carefully are those that had severe swelling near the airway, those that seemed to recover but then develop a new fever weeks later (a possible sign of bastard strangles or immune-mediated complications), and any horse that was treated with antibiotics mid-infection, as these animals are at higher risk of becoming carriers. Post-recovery guttural pouch testing is the only reliable way to close the loop and confirm your horse is truly clear.