This column is the third in a series about plants toxic to dogs, cats and horses. A reminder that on Saturday, Nov. 3, Dr. Gross will be signing copies of his latest book, “Manhunt,” about a true crime family, from noon to 1 p.m. at the Edmonds Bookshop.
By Dr. David Gross
The story continues, with a focus on plants containing toxic alkaloids. Just a reminder, the toxicity of any substance is dependent upon the dose, the greater exposure the greater the toxicity. If you suspect your pet has ingested any of these plants get him or her to your veterinarian as soon as possible.
Plants belonging to the family Amaryllidaceae, the Kaffir Lily (Clivia Lily, Clivies, Caffre Lily, Cape Clivia, Kilvia), Daffodils (Narcissus, Jonquil, Paper White) the Barbados Lily (Amaryllis, Fire Lily, Lily of the Palace, Ridderstjerne) and the Hyacinth (Garden Hyacinth) all contain lycorine and other alkaloids. Ingestion of these plants results in gastric distress with hyper salivation (drooling), vomiting and diarrhea. Ingestion of large quantities of the plant, particularly of the bulbs, can cause convulsions, low blood pressure (hypotension) tremors and cardiac arrhythmias (irregular heartbeats).
The Autumn Crocus (Meadow Saffron) contains colchicines and other alkaloids. Ingestion of this plant can result in irritation of the oral mucous membranes (everything in the mouth and throat) bloody vomiting, diarrhea, shock, multi-organ damage and bone marrow suppression. This one is nasty!
The Yarrow plant (Milfoil) contains glycoalkaloids, monoterpenes and sesquiterpene lactones, all alkaloids and all toxic. Ingestion can result in vomiting, diarrhea, depression, loss of appetite (anorexia) and drooling. The Morning Glory contains at least four different indole alkaloids. After eating this plant your pet can show signs of GI upset, agitation, tremors, disorientation, ataxia (trouble with balance while moving) anorexia. The seeds of Yarrow can cause hallucinations.
The Burning Bush (Wahoo, Spindle Tree) contains both alkaloids and cardenolides. Ingestion can result in GI distress, abdominal pain and weakness. Large doses can result in cardiac (heart) arrhythmias. Bittersweet (Limbing Bittersweet, Waxwork, Shrubby Bittersweet, False Bittersweet, Climbing Bittersweet and American Bittersweet) contains euonymin and sesquiterpene alkaloids. Ingestion of Bittersweet can result in weakness, convulsions and severe gastroenteritis (inflammation of the stomach and intestines).
Over 80 species of Larkspur can be found in North America, most west of the Mississippi River, but are cultivated as an ornamental almost everywhere. In nature the dwarf or low Larkspurs live on lowland slopes and grasslands and are generally less than three feet tall. Tall Larkspurs can grow to four to six feet and are usually found on upper slopes of mountain locations. These plants contain diterpene alkaloids and are more toxic to horses than other species. However horses will no usually consume these plants unless drought conditions exist and there is little else to eat. Dogs and cats have been poisoned from these plants but it is a rare occurrence. As the plant matures it is usually less toxic. Ingestion can result in neuromuscular paralysis along with gastroenteritis, muscle tremors, stiffness, weakness, and convulsions. Animals can die from either cardiac or respiratory arrest.
Ragwort (Golden Ragwort) contains pyrrolizidine alkaloids. It is not palatable but again can be a problem for animals that graze during drought conditions. Dogs and cats will usually not bother this plant, but there are some strange pets out there and poisonings have been reported. Ingestion causes liver failure, and many neurological problems associated with liver failure.
Periwinkle (Running Myrtle, Vinca) contain vinca alkaloids. Ingestion of this plant results in gastroenteritis and depression with moderate intake, tremors, seizures, coma and death if large quantities are consumed. The Lobelia (Cardinal Flower, Indian Pink) contains the alkaloid lobeline. Animals that ingest this plant can develop gastroenteritis, depression and abdominal pain. Large quantities can result in cardiac arrhythmias.
Ambrosia Mexicana (Jerusalem Oak, Feather Geranium) and Bittersweet (American Bittersweet, Waxwork, Shrubby Bittersweet, False Bittersweet, Climbing Bittersweet) may contain euonymin and sesquiterpene alkaloids. Animals ingesting these plants can show signs of gastroenteritis, depression, weakness and convulsions.
Dr. David Gross of Edmonds graduated from Colorado State University’s veterinary school in 1960 and was in private practice for 10 years. He retired in 2006 as Professor and Head of Veterinary Biosciences, at the University of Illinois, Urbana-Champaign. Dr. Gross is the author of “Animals Don’t Blush,” which describes the unique patients and even more unique clients of a veterinary practice in Sidney, Montana in the early 1960s.