Common Name
White snakeroot, Rich weed, white sanicle, white top, squaw weed,
Botanic Name
Ageratina altissima (Eupatorium rugosum)
Plant Family
Asteraceae (sunflower family)
Common in wooded areas
Eastern North America
Animals Affected
All animals including humans that drink the milk from lactating cows and goats.
Toxic Principle
A variety of ketones, collectively known as tremetol are the primary toxins. Tremetol affects the muscles, especially of the heart, causing deneration of the muscle. The cardiac myopathy results in heart irregularity due to conduction abnormalities that can result in death. Tremetol accumulates in the body over time, and once 5-10% of an animal's bodyweight of plant has been consumed, signs of poisoning develop. Tremetol is passed through the milk of lactating animals to their young and to humans that drink the milk of cows, goats etc. grazing on snakeroot.
White snakeroot is a perennial, shrubby plant growing to 4-5 feet in height, with simple, opposite leaves with serrated edges and long petioles. Flowers are small, white, and produced in flat-topped clusters at the ends of branches
Difficulty in chewing and swallowing
Muscle tremors, weakness, ataxia, collapse and inability to rise once down.
Activated charcoal via naso-gastric tube is effective if administered early in the course of poisoning, and should be continued for several days as the tremetol is secreted through the bile and the charcoal will help reduce enteroheptic recycling of the toxin. Supportive therapy to maintain hydration and renalfunction should be instituted as necessary
Cardiovascular system
Rapid, irregular heart rate. Signs of congestive heart failure in more chronic cases.
Respiratory System
Difficulty in breathing because of the myopathy affecting respiratory muscles.
Nervous System
Muscle tremors, incoordination, collapse.
Renal System
Red/brown colored urine due to the presnce of myoglobinurea
Hepatic System
Hepatic degeneration
Diagnostic Tests
Elevation of muscle enzymes (CPK, LDH)
Muscle tremors, cardiac arrhythmias, muscle weakness and red-brown colored urine are suggestive. Cardiac and generalized myopathy, hepatic and renal fatty degeneration are typically seen on histopathology.
Special Notes
Milk from animals grazing snakeroot should not be fed to any animal including humans. The milk may need to be discarded for at least a week or until the milk can be tested to see if tremetol is present. When recognized early, recovery can be expected. A poor prognosis is warranted when myocardial damage has occurred. Jimmy weed (Isocoma pluraflora), a desert plant of south western North America, also contains tremetol and will cause similar poisoning to that of white snakeroot.