White snakeroot, known scientifically as Ageratina altissima, is a poisonous plant native to eastern and central North America, posing significant health risks to both humans and livestock. While livestock can be directly poisoned by consuming the plant, humans are most commonly affected by ingesting contaminated milk or meat from animals that have grazed on white snakeroot.
The Toxic Compound
White snakeroot’s toxicity stems from the compound tremetol. Tremetol is a fat-soluble alcohol that interferes with the body’s metabolic processes, particularly affecting the breakdown of lactate, leading to a buildup of toxic byproducts.
The toxin is present throughout the plant and remains potent even when the plant is dried in hay or after frost. When consumed by lactating animals, tremetol can accumulate in their tissues and their milk. This transfer of the toxin from plant to animal, and then to humans through dairy products, historically led to a severe illness known as “milk sickness.”
Recognizing White Snakeroot
Identifying white snakeroot is important for preventing exposure. This perennial herb grows one to five feet tall. Its stems are smooth or slightly hairy, and they branch in the upper sections where flowers form.
The leaves are an identifying feature, growing oppositely along the stem. They are broadly ovate with pointed tips and serrated edges, three to five inches long. Three prominent veins originating from the leaf base are usually visible. White snakeroot produces clusters of small, white, tuft-like flowers that bloom from late summer into early fall. These flowerheads are arranged in loose, flat-topped clusters at the ends of branches. The plant commonly thrives in wooded areas, forest edges, pastures, and disturbed sites, preferring partial shade and moist soil conditions.
Signs of Poisoning
Symptoms of white snakeroot poisoning can vary depending on the amount consumed and the affected individual or animal. In humans, ingestion can lead to a range of symptoms, often referred to as “milk sickness.” Early signs include nausea, vomiting, abdominal pain, and loss of appetite. As the condition progresses, individuals may experience muscle tremors, weakness, and an acetone odor on their breath. Severe cases can involve constipation, thirst, neurological effects like delirium, and potentially coma, with weakness persisting for weeks in survivors.
For livestock, particularly cattle, horses, sheep, and goats, the poisoning is often termed “trembles.” Affected animals may exhibit muscle tremors, especially after exertion, along with weakness, depression, and a reluctance to move. Other signs include loss of appetite, labored breathing, and a stiff gait. In horses, specific symptoms may include sweating, stumbling, and cardiac irregularities. Onset of signs in animals can range from a few days to several weeks after ingesting the plant.
Responding to Exposure
If white snakeroot poisoning is suspected in a human, immediate medical attention is necessary. Prompt professional care is important for effective symptom management. For animals, veterinary care is crucial.
There are no specific home remedies for white snakeroot poisoning, and treatment typically focuses on supportive care. To prevent further exposure, remove white snakeroot plants from pastures and grazing areas. Avoid consuming milk or meat from animals suspected of ingesting white snakeroot.