Pigweed causes trouble breathing followed by trembling and weakness, then potential coma and death.
Amaranthus retroflexus
Red-root Amaranth
Redroot Pigweed
Common Amaranth
Europe
Tropical America
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Pokeweed
All parts of this plant cause diarrhea, colic, bloody stools, possible anemia, and occasionally death.
Genus: Phytolacca
poke
pokebush
pokeberry
pokeroot
polk salad
polk sallet
inkberry or omb
North America
South America
East Asia
New Zealand
Young pokeweed leaves can be boiled three times to reduce the toxin, discarding the water after each boiling. The result is known as poke salit, or poke salad, and is occasionally available commercially.
Rhubarb
The leaves of rhubarb plants are dangerous to pets. They cause trembling, difficulties breathing, weakness, diarrhea, and increase in drinking and urinating. They can be fatal.
Genus: Rheum
the root known as "rha" or "rheon"
Asia
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Water Hemlock
Water hemlock is very dangerous and kills quickly. It causes dilated pupils, foaming at the mouth, muscles spasms, and convulsions. Death comes within 15 minutes to about 2 hours.
Genus: Cicuta
Cowbane
Northern Hemisphere mainly North America
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Yew
Yew causes problems breathing, trembling and weakness, heart problems, stomach irritation, and very sudden death.
Taxus canadensis
Canadian Yew
central and eastern North America
Taxus canadensis is also being harvested in northern Ontario, Qubec and Atlantic Canada as the plant is a source of the class of poisonous chemicals known as taxanes, which have been a focus for cancer research.