Pokeweed-Phytolacca americana L.-Poisonous plant

Pokeweed

General poisoning notes:

Pokeweed (Phytolacca americana) is a native herb found in the southwestern parts of Ontario and Quebec. The young shoots are used as poke salad and the leaves as a folk medicine or tea. In both cases, the plant material should be boiled at least twice to get rid of the toxin, according to literature reports. Failure to do so has caused poisoning in humans. Ingesting a few berries does not cause problems, but larger quantities, if uncooked, can be toxic to humans. Cattle, horses, sheep, and particularly swine, have been poisoned by ingesting pokeweed plant material. The berries have poisoned young turkeys experimentally (Patterson 1929, Barnett 1975, Callahan et al. 1981, Cooper and Johnson 1984).

Nomenclature:

Scientific Name: Phytolacca americana L.

Vernacular name(s): pokeweed

Scientific family name: Phytolaccaceae

Vernacular family name: pokeweed

Geographic Information

Ontario, Quebec.

Notes on Poisonous plant parts:

Leaves, young shoots, and roots are poisonous. The berries are considered relatively nontoxic to humans, although toxicity to animals and humans has been reported. Barnett (1974) describes experimental poisoning and death in turkey poults.

Toxic parts:

All parts, leaves, mature fruit, roots, stems, young shoots.

Notes on Toxic plant chemicals:

Phytolaccatoxin, a triterpene saponin, has been implicated in pokeweed toxicity. The toxin is water-soluble, which has led to the common assumption that boiling the plant material twice will get rid of toxicity. Such treatment is usually sufficient to remove the toxin (Lampe and McCann 1985).

Toxic plant chemicals:

Phytolaccatoxin

Phytolaccigenin

Chemical diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia, Canada.  

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Cattle

General symptoms of poisoning:

abortion

coma

convulsions

diarrhea

vomiting

Horses

General symptoms of poisoning:

convulsions

diarrhea

gastroenteritis

salivation

vomiting

Humans

General symptoms of poisoning:

abdominal pains

blood pressure, low

breathing, rapid

confusion

diarrhea

dizziness

gastroenteritis

headache

heart rate, elevated

nausea

salivation

stomach cramps

stool, bloody

sweating

thirsty

trembling

unconsciousness

urinary incontinence

vomiting

weakness

Notes on poisoning:

Symptoms of toxicity include sweating, bloody diarrhea, abdominal pains, weakness, incontinence, vomiting, salivation, unconsciousness, tremors, and blurred vision. Ingesting the leaves or young shoots causes toxicity. Sometimes tea made from the leaves can cause poisoning. Symptomatic treatment and replacement of fluids are recommended (Callahan et al. 1981, Jaeckle and Freemon 1981).

Sheep

General symptoms of poisoning:

diarrhea

drowsiness

gastroenteritis

vomiting

Swine

General symptoms of poisoning:

death

gait, unsteady

gastroenteritis

liver, congestion of

muscle twitching

paralysis, posterior

Notes on poisoning:

Swine are most frequently poisoned by pokeweed. Symptoms include staggering, vomiting, posterior paralysis, tremors, and death. Post- mortem findings show swollen, dark liver and severe hemorrhagic gastritis (Patterson 1929).

Turkeys

General symptoms of poisoning:

ascites

gall bladder, enlarged

hock, swollen

weight gain, reduced

Notes on poisoning:

Experimental feeding of mashed berries to turkey poults caused weight-gain reduction, ascites, and swollen hocks, causing unsteadiness. Enlarged gall bladder filled with brown fluid was common in dead birds. Wild birds ingest the berries and spread seeds; no toxic cases have been mentioned. Chickens are not poisoned by the berries (Barnett 1975, Cooper and Johnson 1984).