Creeping Indigo Toxicity in Horses

Creeping Indigo Toxicity in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
Creeping Indigo Toxicity in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is Creeping Indigo Toxicity?

All parts of the plant, including leaves and stems, contain the toxic element that can affect your horse and cause harm. The plant is widespread around the world and causes central nervous system disturbances and once poisoned, there is little hope of recovery. Your horse will most likely love the taste, as most horses seem to find the plant very palatable. Once this plant is established, it is really hard to get rid of. Vigilance is the key here, acting quickly on first sight to destroy it before your horse finds it.

Creeping indigo poisoning is caused by your horse eating this highly palatable perennial legume, resulting in indigofera toxicity that can be fatal to your horse.

Symptoms of Creeping Indigo Toxicity in Horses

Often it is your horse’s personality that gives away its condition, the signs being a quieter than normal and less energetic horse 

  • Loss of appetite
  • Head pressing
  • Lethargy or weakness
  • Flaccid muzzle and lips 
  • Ulceration of the tongue and gums can be severe 
  • Unusual stance
  • Balance problems
  • Stumbling or dragging of the hind feet 
  • Can result in pregnant mares aborting
  • High respiration and heartbeat rates 
  • Increasing weight loss
  • Blinking
  • Rapid eye movements 


  • l. spicata and I. hendecaphylla are two main varieties of creeping indigo, and both have the same toxic punch
  • Nitropropionate (3-NPA ) is one of the two main toxins 
  • Indospicine is the second main toxin present in the highly toxic plant 
  • The Indospicine toxin causes non-neurologic signs as in ulcers 
  • 3-NPA causes irreversible neurologic signs 
  • Corneal damage is possible
  • Both these toxins are extremely potent


Causes of Creeping Indigo Toxicity in Horses

  • The causes of toxicity to your horse comes from the two main toxins present in creeping indigo plant that they eat
  • A build-up of this toxin in your horse can result in severe symptoms that can quickly lead to death 
  • The plant is low and flat, creeping over the land so is not always obvious 
  • Removal using herbicides and hard manual labor is advised


Diagnosis of Creeping Indigo Toxicity in Horses

As with so many toxic cases, by the time the symptoms show it is almost impossible to cure. If you are observant and notice the early signs, removing your horse from the offending plants may enable a recovery, but often there are residual gait abnormalities. Pasture management is vital as the plant spreads easily and quickly to infect fresh pasture. Most people are unaware of the danger this seemingly dainty pretty plant hides, and the plant blends in well with pasture, getting a hold in the bare patches in the paddock and once it gets a foothold, it is hard to eradicate.

Suspicion of ingestion of the creeping indigo plant warrants a veterinary consultation as soon as possible. The veterinarian will note both neurological and non-neurological signs such as rapid eye movement, head pressing, flaccid muzzle and lips, abnormal gait, and sleepiness. White blood cell and electrolyte markers may appear abnormal, though other laboratory work does not typically give definitive answers.

A physical exam may show signs of ulcerations on the tongue and lips. The veterinarian may decide to walk the pasture in order to identify the creeping indigo or other noxious plants present in the area.



Treatment of Creeping Indigo Toxicity in Horses

There have been cases when the affected horse has recovered, but there are far more cases where recovery was impossible. Several treatments have been trialed such as peanut meal and gelatine (because of their arginine rich protein sources) but have had no effect on affected animals. 

Thiamine was suggested as a trial treatment for nitro toxicity but studies showed this often to be ineffective. Confinement in a quiet restful area is recommended in order to prevent injury to your horse. The veterinarian may provide supportive therapy in the form of symptomatic treatments. This is done when no specific treatment is available. Removal of your horse from any area where this plant grows and indeed, removal of the plant itself is the best course of action.

Your horse may become addicted to this plant as so many other horses have when it has invaded their pasture. Sadly, they seem to love the taste which leads to high levels of the plant being eaten. This concentration of toxin then takes over and the results are irreversible. For horses that do recover, they are the lucky ones but may still be affected by an unusual walk or stance. Prevention at this stage is the only known course of action to ensure your horse is safe and his food is quality and health promoting. That is why it is so vital to destroy any sign of this pretty, seemingly harmless plant. Ensuring your paddocks are not overgrazed will help inhibit this plant as they like sparse grass areas to get their growth cycle going. Herbicides are effective but refer to the product labels for specific instructions.



Worried about the cost of Creeping Indigo Toxicity treatment?

Pet Insurance covers the cost of many common pet health conditions. Prepare for the unexpected by getting a quote from top pet insurance providers.

Recovery of Creeping Indigo Toxicity in Horses

If you are observant and see the creeping indigo in your pasture, removing your horse immediately from the area may save its life. There have been recoveries recorded from horses who have eaten this plant, but usually these animals have been blessed with observant owners who got them out of the paddock in time. This plant is double trouble because it tastes nice to the horse, who then wants more of it. So even if your horse has quality grazing and plenty of food, if there is creeping indigo around, to your horse it is a most enjoyable forage. There is no doubt that leaving your horse exposed to this weed can be fatal.



Creeping Indigo Toxicity Questions and Advice from Veterinary Professionals

Need pet insurance?
Need pet insurance?

Learn more in the Wag! app

Five starsFive starsFive starsFive starsFive stars

43k+ reviews


© 2022 Wag Labs, Inc. All rights reserved.