Master List of Poisonous Plants

White snakeroot

White snakeroot/Ageratina altissima

Info about plant-

Ageratina altissima, also known as white snakeroot, richweed, white sanicle, or tall boneset, is a poisonous perennial herb in the family Asteraceae, native to eastern and central North America.

Plants are upright or sometimes ascending, growing to 1.5 m tall, producing single or multi-stemmed clumps. They are found in woods and brush thickets where they bloom mid to late summer or fall. The flowers are a clean white color and after blooming, small seeds with fluffy white tails are released to blow in the wind. This species is adaptive to different growing conditions and can be found in open shady areas with the open ground; it can be weedy in shady landscapes and in hedgerows. There are two different varieties Ageratina altissima var. angustata and Ageratina altissima var. roanensis (Appalachian white snakeroot); they differ in the length of the flower phyllaries and shape of the apices.

Toxicity

White snakeroot contains the toxin tremetol; when the plants are consumed by cattle, the meat and milk become contaminated with the toxin. When milk or meat containing the toxin is consumed, the poison is passed on to humans. If consumed in large enough quantities, it can cause tremetol poisoning in humans. The poisoning is also called milk sickness, as humans often ingested the toxin by drinking the milk of cows that had eaten snakeroot.

Symptoms in humans include-

· loss of appetite

· nausea

· weakness

· abdominal discomfort

· reddened tongue

· mucous membranes

· abnormal acidity of the blood

· accumulation of ketone bodies.

In instances of serious poisoning-

· convulsions

· coma may culminate in death.

In persons who survive, weakness may persist for weeks.

The plants are also poisonous to horses, goats, and sheep. Signs of poisoning in these animals include depression and lethargy, placement of hind feet close together (horses, goats, cattle) or held far apart (sheep), nasal discharge, excessive salivation, arched body posture, and rapid or difficult breathing.

This plant may serve medicinal purposes. Root tea has been used to treat diarrhea, kidney stones, and fever. A root poultice can be used on snakebites.