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
Phytolacca americana L.
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
Phytolaccatoxin
Phytolaccigenin
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).
