As a horse owner, you need to be aware of the disturbing side effects of medicating horses with “Bute”. Phenylbutazone a non-steroidal anti-inflammatory drug has been in common use for more than 70 years in equine veterinary medicine to relieve pain and inflammation.

The harm it causes to horses even after very short term use has been well documented over the past 20 years.

So why are so many horse owners and vets still so quick to reach for bute as a medication for pain relief and inflammation?

The answer is despite the knowledge of the damage it can do, the culture of using it is so ingrained, hardly anyone is thinking outside the square for safer alternatives. Or looking to treat causes.

Phenylbutazone (PBZ) is second only to aspirin as one of the oldest nonsteroidal anti-inflammatory drugs (NSAIDs). It was introduced into veterinary medical practice in the 1950s and still remains one of the more commonly used NSAIDs in the horse (Tobin et al., 1986).


Horses treated with bute, especially at high doses or for long periods of time, can develop ulcers in their stomachs or colon, kidney damage and, less commonly bone marrow suppression.

Bute is often used for any pain and inflammation caused by infection. The inflammation is a key response to the infection. The body has directed extra blood flow to the infected area to get infection-fighting agents there. By giving bute you are likely to give the infection a dangerous helping hand.

Research conducted in 2000 found that it can slow the production of joint cartilage and delay bone healing; it also interferes with thyroid function.

The study was performed by scientists in The Ohio State University’s (OSU) Orthopaedic Research Laboratory and appeared in the American Journal of Veterinary Research. Eleven sound, radiographically normal 18- to 30-month-old horses were used in the study.

“The results weren’t that surprising, actually, that drugs which suppress inflammation might also slow healing.” Alicia Bertone, DVM, Ph.D., study investigator in Equine Clinical Medicine and Surgery, OSU.

(A previous human study showed that abdominal incisions healed more slowly in patients treated with NSAIDs).

“Research shows that prolonged use of bute can cause some adverse effects in horses as soon as three days after initial treatment.” Lead researcher, Rebecca McConnico, Associate Professor at Louisiana State University’s School of Veterinary Medicine – 2009

The effects include protein loss, lowered white blood cell counts, blood-flow changes in the right dorsal colon, and changes in volatile fatty acid activity.

During this study, led by McConnico, eight horses were either administered bute at 8.8 mg/kg for 21 days or were part of the control group given corn syrup. The horses were closely monitored using physical examinations, blood samples, arterial blood flow analysis examinations, and samples collected from the right dorsal colon as well as other analyses.

Horses receiving bute experienced abnormally low protein concentrations in the bloodstream beginning as early as three days after the initial administration of bute, lowered numbers of white blood cells starting three to six days after initial treatment and lowered concentrations of one type of volatile fatty acid in just two weeks.

“Volatile fatty acids are largely thought to be responsible for water absorption in the distal part of the colon in horses. In addition to these results, two horses developed colitis while receiving bute and were removed from the study and hospitalised. Without the detailed measurement undertaken in this research, the outward signs of these effects would be subtle.” Dr. Rebecca McConnic.


The best way to find safer alternatives is to consult a trained equine herbalist who will carefully examine the cause of the inflammation and pain and then prescribe and dispense herbal medicines to hasten to heal. There are many pathways in the body to do this –  stimulating circulation, preventing bleeding and bruising,  strengthening immunity, providing liver and kidney detoxification, and targeting bacteria and viruses.

The herbal alternative to bute is Devil’s Claw which I always use together with Meadowsweet, which compliments the properties of Devils Claw.  These are very safe to use in the short to medium term but I am against using them in the long term as there are better choices.


Bute and Devil’s Claw are both commonly used in the long term to try to help horses with arthritis.  This is not a good option.  Both can be replaced with herbal medicines which improve joint mobility which then effectively relieves pain.

I never prescribe Devil’s Claw and/or Meadowsweet on their own, always with a prescription or formula to treat the cause of the problem.


Laminitis is a good example,  as in this case, it is important to get the inflammation under control quickly and to relieve pain, which can be achieved effectively with Devil’s Claw & Meadowsweet, together with a laminitis prescription to stimulate circulation in the hoof, especially the venous return and the capillary circulation and to provide liver detoxification.  Management is always important for the relief of pain too.


I have had many reports over the last few years of vets using bute to treat the pain of colic, I find this extraordinary, as none of the revered vets of my time would ever have done such a thing.  There are some very good drugs for treating colic, but it is essential to determine what type of colic, impaction, spasmodic, gas or worse?

The right choice of herbs provides rapid relief from symptoms of colic, then causes can be treated.  My colic relief formula which contains the strong anti-spasmodic herb Valerian along with Chamomile & Peppermint works on all types of colic.

If the cause of the colic is sand impaction this can be rectified with regular oral dosing with cold-pressed linseed oil and regular feeding of millet and linseed porridge.


As research has shown giving bute to horses with infections of any kind will more than likely hamper healing.  Modern research has provided us herbalists with a whole raft of herbal medicines which are effective against virtually all bacteria and viruses.  At the moment I am treating a Thoroughbred horse with a resistant staph infection who is progressing tremendously well-using herbs targeted to this infection systemically, and topically Calendula tea and raw honey.

There are also broad-spectrum herbal infection fighters such as Garlic, Rosehips, and Echinacea, which is a good place to start.

If you are sceptical – why not try the herbal approach?  Your horses will tell you the results!

© Victoria Ferguson Dip.Herb.Med.  21 July 2020