Pet Topics

Toxic Foods

by Dr. Ku

Did you know???

Grapes and raisins could be potentially toxic to dogs, and probably cats as well. It is currently unknown what part of the grape causes renal failure, but some animals are particularly sensitive to ingestion of grapes and raisins, to the point that a small amount can lead to kidney failure in some susceptible animals. Not all dogs and cats are susceptible, but those that are can become very ill. Until more is known about this potential danger, it is best to avoid giving them to your pet in appreciable amount, and to be sure they are not available through refuse containers, countertops and well-meaning visitors.

Xylitol, a natural sugar alcohol that has recently been used in some sugar-free chewing gums, candies, and baked goods can be harmful to dogs as well. It is somewhat dose dependent, but can cause marked hypoglycemia (low blood sugar) and seizures in as short as 30 minutes. More information is available on the ASPCA website at

Chocolate contains theobromine which is toxic to dogs as well. Fortunately for most dogs, milk chocolate contains a relatively small amount of this product, whereas baking chocolate or dark chocolate, contain much larger amounts. Theobromine can cause heart arrhythmias, tachycardia (fast heart rate) and even seizures. It is somewhat dose dependent, but a small dog (such as a Chihuahua) would only need to eat an eighth of a bar of baking chocolate to ingest a potentially fatal dose. What makes chocolate so dangerous for most dogs is that they will often consume large amounts at once (having no fear of weight gain or acne to stop them!), and the added ingredients of fat and sugar in many chocolate products can also cause severe gastroenteritis.

And don't forget about onions. Onions (and garlic) contain a chemical which both dogs and cats are susceptible to that can cause severe anemia and blood in the urine. Whether or not onions are cooked does not necessarily lessen the toxic effect, and ingesting as little as 0.5% per kg body weight can be toxic. That translates to less than 1 tablespoon for a 5 lb. pet (e.g. Chihuahua), 1/4 cup for a 20 lb. pet, and 2/3 cup for a 60 lb. pet. Dogs and cats are likely to eat more if onions are cooked because they often carry the flavor of whatever they were cooked in as well. Kittens and cats seem especially susceptible to the toxic effects and can be affected by onion and garlic powders. The anemia can be profound and may even require a transfusion. The effects tend to be most pronounced 2-4 days after ingesting onions, and can be cumulative too (i.e. smaller amounts on a regular basis can also lead to toxic effects). Garlic is less likely to be consumed in larger quantities, but again, when used in cooking they can be ingested in larger amounts more readily.

The important thing to keep in mind is that not everything we eat is good for our pets, and often it is exactly the opposite. A covered garbage container, and extra care to put our food out of reach of our pets can do a lot for preventative health care. Remember, their keen sense of smell will lead them to it - every time!