Grape Toxicity

For the past few years, there have been discussions flying around the veterinary community as to whether grapes were toxic to dogs and what attribute of the grape was actually causing a problem. Dogs were suddenly appearing with signs of kidney failure that had no known exposure to any commonly known toxins such as anti-freeze. With the Pet Poison Control Center having operated in Illinois now for over 10 years, enough data has been collected to say that yes, there is a connection in some dogs between ingestion of grapes or raisins and kidney disease. Researchers are still looking in to what it is in the grape that might be causing the problem. Some were speculating that it was a pesticide on the grape which has now been disproven. Others thought it was a substance in grape seeds which has also been disproven. The odd thing about this apparent toxicity is that not all dogs are susceptible to it and the current thought is that the problem is due to something in the grape skin itself. Despite on going research, I would recommend that no dog be given grapes or raisins. It is obviously not worth the risk.

The other unexpected toxicity issue which has popped up is what is called Cycad toxicity or poisoning associated with chewing on parts of a palm trees in the Cycad family. Palm trees in the Cycad family, including Saga and Cardboard Palms, have a potent toxin that causes rapid and severe liver damage. I would advise not including these palms in landscaping where dogs might come in contact with them. If these palms are around, obviously prevent the dog from putting any of the plant in his or her mouth. Below is a partial list of common plants that can cause toxicity issues with dogs.


Potentially Cardiotoxic Plants:
Lily of the Valley- Convallaria majalis
Oleander- Nerium oleander
Rhododendron species
Japanese, American, English, and Western Yew- Taxus species
Foxgove- Digitalis purpurea
Kalanchoe species
Kalmia species

Plants that could cause kidney failure:
Rhubarb (Rheum species)- leaves only

Plants that could cause liver failure:
Cycad, Sago, Zamia Palm (Cycad species)
Amanita mushrooms

Plants that can cause multi-system effects
Autumn Crocus (Colchicum species)
Castor Bean (Ricinus species)

Plants containing Calcium Oxalate Crystals

Peace lilies, Calla lilies, Philodendrons, Dumb Cane, Mother in Law, and Pothos plants contain insoluble calcium oxalate crystals. These crystals can cause mechanical irritation of the oral cavity and tongue when plant material is ingested. Clinical signs that are usually include regurgitation, oral pain, trouble eating, and anorexia. The signs are rarely severe and usually respond to supportive care.

Peace lilies (Spathiphyllum sp)
Calla lily (Zantedeschia aethiopiea)
Philodendron (Philodendron sp)
Dumb Cane ( Dieffenbachia sp)
Mother in Law plant (Monstera sp)
Pothos (Epipremnum sp)

Thanks everyone for taking such good care of our dogs and continually watching out for their well being!

Jerry L. Edington, D.V.M.
Director of Veterinary and Breeding Services