Lantana Poisoning in Horses

Key Takeaways

Lantana poisoning is a condition that occurs when horses ingest large amounts of the lantana plant, also known as yellow or red sage. 

Lantana camara plants contain compounds called triterpenoids that can cause liver damage, liver failure, and photosensitization

• Common symptoms of lantana toxicosis include appetite loss, frequent urination, lethargy, sloughing skin, and yellowing of the gums and eyes

• Diagnosis is based on symptoms, bloodwork and history of exposure

• There is no antidote or specific treatment for lantana poisoning; treatment is focused on decontamination and supportive care

• Prognosis varies from guarded to poor and depends on the amount of toxin ingested and the severity of liver damage

A Closer Look: What is Lantana Toxicosis in Horses?

Lantana plants are native to the American tropics and are a resilient plant with populations all over the world. The ingestion of all parts of the Lantana camara plant can cause poisoning in horses. Lantana poisoning in horses leads to life threatening liver damage.

No antidote for lantana toxin exists, and treatment options are limited; as such, prevention is the only way to ensure horses do not develop this condition. The best prevention measures are providing plentiful, uncontaminated feed and removing lantana plants from pastures.

Risk Factors

Lantana toxicosis is rare in horses. This toxicosis is a life-threatening condition and must be treated as an emergency. 

Lantana toxicosis can cause photosensitization due to liver failure. Symptoms of photosensitivity include:

• Redness after exposure to sunlight

• Swollen skin (edema)

Skin peeling or sloughing

• Skin that oozes or weeps

• Excessive tearing

Photosensitization from lantana toxicosis is generally followed by death. 

Horses living in the southern United States, tropical regions of central and south America, and Australia are at a higher risk of developing lantana toxicosis.

Possible Causes

Lantana camara is a perennial flowering shrub commonly found in the southern United States, tropical regions of south and central America, and Australia. 

Lantana plants contain triterpenoids, a group of organic chemicals that, when ingested, cause liver damage, photosensitivity, and death.

Main Symptoms

Main symptoms of lantana toxicosis include:

Yellow gums, eyes, and skin

• Swollen skin (edema)

• Red skin after exposure to sunlight 

• Lethargy

• Excessive urination  

Reduced appetite

Testing and Diagnosis

There is no specific diagnostic test for lantana toxicosis. Horses presenting symptoms usually undergo the following diagnostics: 

• Physical examination 

• Bloodwork

• Ultrasound of the liver

• Liver biopsy

Steps to Recovery

There is no antidote for lantana toxicosis, and treatment is supportive and symptomatic. Treatment options are limited and include:

• Activated charcoal in cases of ingestion caught early

• Removing the source of lantana 

• Protection from direct sunlight

• Topical treatment of skin wounds

Note: always consult a veterinarian before administering activated charcoal. 

Prognosis of lantana toxicosis varies from guarded to poor. The outcome depends on the amount of toxin ingested and the severity of liver damage. 

Death generally occurs 1 to 4 weeks after the onset of symptoms, particularly in cases where photosensitization and liver failure develops.


Lantana toxicosis is not contagious. 

Horses that never ingest lantana plants do not develop toxicosis. Prevention strategies include: 

• Providing abundant uncontaminated feed 

• Removal of lantana plants from pastures

• Pasture and feed analysis prior to feeding 

Removal of lantana from pastures is the best way of preventing lantana toxicosis, but attention is warranted as many pesticides and herbicides can be toxic to horses.

Is Lantana Toxicosis Common in Horses?

Lantana toxicosis is a rare condition in horses.

Typical Treatment

• Supportive care

• Removal of the horse from lantana containing pastures

• Protection from direct sunlight 

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