Buttercup Poisoning in Horses

Buttercup Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
Buttercup Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is Buttercup Poisoning?

The buttercup is also poisonous to other animals such as cattle, goats, pigs, dogs and cats.  When the plant cells are chewed on (broken down), they cause a chemical reaction, which turns the enzyme ranunculin into the poisonous oil protoanemonin. The plant is most toxic in its early development through the flowering stage of the buttercup, usually during the months of April to August.  

Typically, horses do not eat the buttercup plant because it is bitter tasting. If the pollen of the buttercup is inhaled it can also be irritating to the horse’s nostrils. The effects of buttercup poisoning can be mild to moderate, depending on how much of the toxin was ingested.

The buttercup (Ranunculus spp) is a wild plant that has bright yellow flowers, which have the shape of a cup.  The buttercup’s flowers, seeds, stems and leaves are toxic if ingested by a horse.  The flowers of the buttercup have a high concentration of the enzyme ranunculin.

Symptoms of Buttercup Poisoning in Horses

Symptoms may include:

  • Blisters on the lips
  • Lesions in the mouth
  • Swelling of the facial tissue
  • Drooling 
  • Colic
  • Diarrhea with blood
  • Blood tinged urine
  • Decreased appetite
  • Low pulse rate
  • Convulsions
  • Skin twitching
  • Paralysis


Causes of Buttercup Poisoning in Horses

Causes of buttercup poisoning may be from:

  • The horse accidentally eats the weed while foraging in an overgrown pasture
  • The absence of other plants to forage on
  • Finding the buttercup palatable despite the bitterness


Diagnosis of Buttercup Poisoning in Horses

Diagnosing buttercup will most likely result from the evaluation of clinical signs. Horses who have eaten the plant will be salivating excessively and have blisters in the mouth as well as on the lips. Diarrhea is also typical in horses who have ingested the buttercup. 

If your equine has consumed a large amount of this toxic plant, the veterinarian may note twitching of the muscles, and in severe cases, convulsions may lead to death. Fortunately, documentation shows that equines do not normally like to graze on this plant and will avoid it unless they are very hungry. Because of this, the oily substance, ranunculin, does not affect horses to the extreme. Your veterinarian may choose to perform blood work however, in order to determine the level of toxicity. With plant poisonings, blood markers can be abnormal and this will indicate the level of treatment needed. Sometimes the feces of a horse who has consumed buttercup will have a foul odor.



Treatment of Buttercup Poisoning in Horses

Unless the toxicity of the buttercup ingestion is severe, symptoms will begin to dissipate once the offending plant is no longer accessible to your horse. Dangerous levels of toxicity are rare due to the unpalatability of the buttercup. In the rare cases of extreme toxicity, treatment will be symptomatic and may include therapy for colic and medication for symptoms such as convulsions.

Typically though, the blisters in your horse’s mouth will be treated with antibiotics if needed to help prevent bacterial infection. The lesions or blisters on the horse’s nostrils, face and lips will be prescribed topical antibiotic cream. The poisonous oil protoanemonin can cause your horse’s stomach lining to become irritated; the veterinarian may recommend a demulcent to help coat the gastrointestinal tract.



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Recovery of Buttercup Poisoning in Horses

Interestingly, the buttercup is no longer toxic once dried, and is safely eaten in hay. To avoid fresh buttercup poisoning from reoccurring, the wild plant should be permanently removed from the pasture. The buttercup plant is not only toxic to animals, it also depletes potassium from the soil.  

Tilling the soil and spraying any regrowth is the usual method for removing buttercup. This plant can easily take over a field in times of dry weather; consult your local agricultural expert for advice on hardy, safe grasses that can be planted in your paddocks and pasture.



Buttercup Poisoning Questions and Advice from Veterinary Professionals




Quarter Horse


22 Years


2 found helpful


2 found helpful

Has Symptoms

Blisters Around Muzzle, Lathargic,

My horse had foundered so i have him in a dry lot and feed him hay but the dry lot has some buttercups which we did treat but havent died yet - he has blisters around his muzzle, and isnt himself. would it help to mow down the buttercup - on weekends after he finishes his hay i put a grazzing muzzle (which he hates) on him and let him in the other pastures. so i have a horse now with foundering issues and buttercup issues. Suggestions

May 6, 2018

tipper's Owner


Dr. Michele K. DVM


2 Recommendations

The buttercup can cause local irritation similar to what you're describing, and it may help to get rid of the buttercup so that he can't eat it, yes. Typically the plant is quite bitter, but he may be eating it with the hay and not noticing the taste. If the lesions on his mouth do not improve, his veterinarian should look at it and see if he needs any treatment to help resolve that problem. I hope that things go well for him.

May 6, 2018

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