Some foods we eat every day can be very dangerous for a dog. In some cases, a few grams are enough to cause severe poisoning.

Most accidents happen simply because a dog found food left on a table, in a shopping bag, or in the trash. Veterinary poison control centers also report that food poisoning is one of the most frequent emergencies in dogs.

Here are the foods whose toxicity is best documented today.

Fresh grapes, raisins, sultanas: a risk of acute kidney failure

This is one of the most feared food poisonings.

Several studies have shown that some dogs develop acute kidney failure after eating grapes or raisins. The lesions primarily affect the renal tubules and can rapidly progress to severe kidney failure.

The mechanism is now better understood: tartaric acid appears to be the main culprit for this toxicity.

The real problem is that there is no dose considered safe. Some dogs remain unharmed after a significant amount, while others develop kidney failure after just a few grapes.

To remember: any ingestion of grapes or raisins should be considered a veterinary emergency.

Onion, garlic, leek, and chives: a risk of anemia

Allium family plants contain sulfur compounds capable of damaging red blood cells.

In dogs, this can cause hemolytic anemia, sometimes several days after ingestion.

All forms are concerned:

• raw;

• cooked;

• dehydrated;

• powdered;

• present in prepared dishes.

Garlic or onion powders are particularly problematic because they are much more concentrated.

It is still sometimes read that garlic would be beneficial for dogs in small doses. However, current scientific data calls for caution: garlic is also considered a toxic food and should not be given voluntarily.

Chocolate, cocoa, and caffeine: excessive stimulation of the heart and brain

Chocolate mainly contains theobromine, but also caffeine.

In dogs, these molecules are eliminated much more slowly than in humans, which explains their toxicity.

The richer a chocolate is in cocoa, the more dangerous it is:

• cocoa powder;

• dark chocolate;

• baking chocolate.

Milk chocolate is less concentrated, and white chocolate contains very little, but is still not recommended.

The first signs are generally:

• vomiting;

• agitation;

• panting;

• tremors;

• increased heart rate.

In severe cases, cardiac arrhythmias, seizures, or coma may occur.

Xylitol: an absolute emergency

Xylitol is a sweetener found in many "sugar-free" products:

• chewing gums;

• candies;

• toothpastes;

• certain medications;

• certain peanut butters;

• certain food supplements.

In dogs, it causes a massive release of insulin, which can lead to hypoglycemia in less than an hour.

In some animals, acute liver failure may also occur.

Unlike humans, dogs react extremely sensitively to xylitol.

The slightest doubt warrants immediate veterinary consultation.

Macadamia nuts: a neurological syndrome, usually reversible

Macadamia nuts can cause:

• significant weakness;

• difficulty walking;

• tremors;

• vomiting;

• sometimes fever.

Symptoms generally appear within twelve hours of ingestion and usually disappear within one to three days.

The mechanism responsible remains unknown.

Alcohol and raw bread dough

Alcohol is toxic to dogs, even in small quantities.

It can cause:

• vomiting;

• loss of balance;

• drowsiness;

• breathing difficulties;

• coma.

Raw bread dough presents a double risk:

• yeast produces alcohol during fermentation;

• the dough continues to expand in the stomach, which can lead to significant digestive distension.

Moldy nuts, spoiled food, and mycotoxins

Moldy nuts, seeds, cereals, or food scraps can contain mycotoxins, particularly tremorgenic toxins.

In dogs, these can cause sometimes impressive neurological signs: agitation, tremors, gait disorders, hypersalivation, vomiting, hyperthermia, and even seizures in severe cases.

The risk therefore concerns not only the "food" itself but also its preservation state. A nut, a piece of bread, compost waste, or food dropped outdoors can become dangerous if contaminated by mold.

To remember: moldy or spoiled food should never be given to a dog, even in small quantities.

Summary: risk levels by food

This table is intentionally simplified. 

In practice, the severity always depends on the quantity, format, dog's weight, time elapsed, and initial clinical condition.

For grapes and xylitol, maximum caution is required. 

Other foods also require caution

Literature also describes other foods that may be toxic depending on the quantity ingested or the context:

• raw cookie dough containing yeast 
• nutmeg 

• certain fruit pits that can cause digestive obstruction 

• very fatty foods that can promote pancreatitis in some dogs.

Not all have the same level of evidence or the same frequency of poisoning, but they are worth knowing.

What to do if your dog has eaten toxic food?

Never wait for symptoms to appear.

Contact your veterinarian or a veterinary poison control center immediately.

Do not try to make your dog vomit without veterinary advice. Depending on the ingested product or its clinical condition, this can be dangerous.

When you call, if possible, have the following information ready:

• the food concerned;

• the approximate quantity;

• the dog's weight;

• the time of ingestion;

• the packaging or ingredient list if the product is processed.

Prompt treatment significantly improves the prognosis for many intoxications.

Not all foods on this list present the same level of risk. Some, like grapes or xylitol, warrant immediate care. For others, the severity depends more on the quantity ingested, the dog's size, and its health condition. When in doubt, a call to the veterinarian will help assess the situation and decide on the course of action.

________________________________________________________________________________________________

Sources

1. Kovalkovicová, N., Šutiaková, I., Pistl, J., & Šutiak, V. (2009). Some food toxic for pets. Interdisciplinary Toxicology, 2(3), 169–176.
2. Cortinovis, C., & Caloni, F. (2016). Household food items toxic to dogs and cats. Frontiers in Veterinary Science, 3, 26.
3. Eubig, P. A., Brady, M. S., Gwaltney-Brant, S. M., Khan, S. A., Mazzaferro, E. M., & Morrow, C. M. K. (2005). Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs. Journal of Veterinary Internal Medicine, 19(5), 663–674.
4. Schweighauser, A., Francey, T., Gurtner, C., Kupferschmidt, H., & Kupper, J. (2020). Acute kidney injury in dogs after ingestion of cream of tartar or tamarind fruits. Journal of Veterinary Internal Medicine, 34(5), 2020–2025.
5. Bates, N., Sharman, M., Lam, A., & Edwards, N. (2023). Investigating tartaric acid as the toxic principle in grapes and raisins. Veterinary Record, 192(2), 73.
6. Piscitelli, C. M., Dunayer, E. K., Aumann, M., & Leiter, C. (2010). Xylitol toxicity in dogs. Compendium: Continuing Education for Veterinarians, 32(2), E1–E4.
7. Salgado, B. S., Monteiro, L. N., & Rocha, N. S. (2011). Allium species poisoning in dogs and cats. Journal of Venomous Animals and Toxins including Tropical Diseases, 17(1), 4–11.
8. ASPCA Animal Poison Control Center. People foods to avoid feeding your pets. American Society for the Prevention of Cruelty to Animals.
9. ASPCA Animal Poison Control Center. Toxic and non-toxic plants / foods database. American Society for the Prevention of Cruelty to Animals.