Fruits & Vegetables That Are Toxic to Dogs

Written by Hannah Miller and reviewed by horticulturist Elizabeth Smith. Published to Blog on the 4th July 2021.

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Hello, my name is Hannah Miller, and I’m the co-owner and contributor here at DIY Gardening.

It’s not only pesticides and weed killers that can harm dogs, there are many garden plants, fruits and even vegetables that are toxic.

Is your dog at risk of harm due to fruits and vegetables grown in your garden?

Below you’ll find five common fruits and vegetables that are capable of killing a dog; I’ve also listed the symptoms and suggested next steps, should your dog consume these.

Hannah Miller

Hannah Miller

Grapes and Raisins


Grapes, raisins and Zante currents are very toxic to dogs, and studies have shown as little as 4-5 grapes is enough to cause renal (kidney) failure and kill an 8kg dog.

While most dogs won’t eat these, raisins and currents are often found in sugary cereal bars and are sometimes mixed with chocolate and other foods that dogs are attracted to.

Common Symptoms

Symptoms usually appear 6-12 hours after ingestion and may include:

  • Vomiting.
  • Diarrhoea.
  • Problems with urination.
  • Lethargy.
  • Weakness.
  • Dehydration.
  • Tremors.


If you suspect your dog has consumed grapes, raisins or Zante currents, you should consult a veterinary professional as soon as possible, regardless of the quantity consumed.

Treatment to prevent kidney failure should be carried out by a vet and often includes:

  • Induced vomiting.
  • Activated charcoal to absorb toxins in the gut.
  • Administration of intravenous fluids.
  • Renal function and fluids monitoring for a minimum of 48 hours.

If left untreated, renal failure can occur within 24-72 hours and is fatal in most dogs.




Marketing experts often refer to avocados as a Superfood offering incredible health benefits.

Unfortunately for dogs, the skin and, to a lesser degree the flesh, contain Persin, a fungicidal toxin.

Some dogs can tolerate Persin, while others show signs of toxicity after consuming a large amount.

Avocados are also a fatty fruit, and excess consumption can lead to stomach irritation and excess gas.

Birds, horses, sheep, goats and rodents are also susceptible to avocados, and you should keep them away from this fruit as well.

The avocado pit can’t be easily digested in the gut so it may become trapped if your dog consumes it.

Common Symptoms

Some dogs will show no symptoms of Persin toxicity and will be just fine; others may show the following symptoms, which may appear 6-12 hours after ingestion:

  • Vomiting.
  • Diarrhoea.
  • Stomach pain.


If you suspect your dog has consumed a pit, it may need a scan so the vet can determine the next course of action, which could be surgery.

Persin toxicity treatment often includes:

  • Monitoring.
  • Fluids.
  • Ant-acids.
  • Anti-nausea medicine.

The prognosis for Persin toxicity is generally very good. 

As for pits and their removal, this will depend on the severity and how much time has passed since ingestion.




Rhubarb is a popular vegetable grown for use in crumbles, pies and desserts where it’s mixed with sugars.

These dishes could attract dogs, but there is also a risk that dogs could dig up the plants in the garden and chew on the stalks and leaves, which contain the toxin calcium oxalate.

Common Symptoms of Toxicity

Rhubarb consumption is rarely fatal to dogs, but if a small dog consumes a large enough quantity, poisoning and, in rare cases, kidney failure can occur.

Symptoms to look out for are similar to food poisoning in general:

  • Vomiting.
  • Diarrhoea.
  • Stomach pain.
  • Changes in drinking and urination.
  • Reduced appetite.


If you suspect your dog has consumed rhubarb, consult a veterinary surgeon as your pet may need fluids to protect the kidneys and possibly a calcium supplement. 


Nuts and Seeds

Nuts and seeds

As a general rule of thumb, dogs shouldn’t be given seeds or stones from fruits such as apples, peaches, plums, etc., as they contain cyanide, which could harm them.

Also, any seed that’s gone mouldy poses a risk to dogs, so be wary of leaving these out for birds in the garden.

The vast majority of nuts are safe for dogs to eat, but one should be wary of additives that are fine for humans but dangerous for dogs. An example is Xylitol, a sweetener often found in peanut butter, it’s particularly harmful to dogs, and small amounts can and have killed dogs in the past.

Black walnuts and macadamia nuts are toxic for dogs, also be aware that many fruit and nut bars created for humans may contain sugars and chocolate that could attract dogs.

Common Symptoms of Nut Toxicity

The most common cause of nut toxicity is from the ingestion of macadamia nuts, and 2.4g of nuts per kg of body weight is enough to cause early signs of poisoning, usually within 12 hours of ingestion. Experiments have shown that up to 20g/kg can cause:

  • Vomiting.
  • Diarrhoea.
  • Muscle weakness.
  • Changes in drinking and urination.
  • Reduced appetite.


Most dogs will recover without the need for treatment if they have only consumed a small amount.

For dogs who have consumed more than 1-2g per kg of body weight, a veterinary surgeon may decide to induce vomiting and then administer activated charcoal to absorb any toxins that remain in the gut. IV fluids may also be needed to protect the kidneys and prevent dehydration.


Onions Chives and Garlic


Onions, chives, leeks and garlic are all harmful to dogs if ingested but the most dangerous are the concentrated forms of onion and garlic often found in kitchens. 

For example, one teaspoon of garlic powder is equivalent to 8 cloves of garlic.

Whether consumed cooked, raw or concentrated, all can cause gastrointestinal irritation and red blood cell damage.

Common Symptoms of Allium (Onion Family) Toxicity

It may take several days for symptoms to appear in dogs:

  • Depression.
  • Weakness.
  • Intolerance to exercise.
  • Weight loss.
  • Appetite loss.
  • Changes in urine colour.


A veterinary surgeon may decide to induce vomiting if the ingestion occurred recently. Activated charcoal may absorb some remaining toxins preventing their entry into the blood system. Supplementary oxygen may help prevent further red blood cell damage, and IV fluids could be delivered to relieve dehydration and protect the kidneys. A blood transfusion may also be considered.


Other Foods That Are Dangerous to Dogs

In addition to the above, you shouldn’t feed your dog these:

Chocolate – Just 11g of dark chocolate is enough to harm a small dog (source).

Corn on the cob – The corns are safe, but the cob can cause a bowel obstruction as dogs cannot digest it (source).

Cooked bones – Many dog owners think that chicken bones are dangerous for dogs. In fact, all cooked bones are a risk as they can split and damage the intestines (source).

Xylitol – A sweetener that’s very toxic to dogs, it can be found in hundreds of sweets, desserts and other foodstuffs (source).

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Meet The Author: Hannah Miller

Hannah is a former NHS administrator, mother of two and keen gardener with a horticulture qualification who loves growing new plants and experimenting in the garden.

She enjoys gardening as much as she cares about the environment and likes to share her knowledge with others.

This year is all about pollinators, and Hannah has set herself the goal of only buying new plants that attract pollinators; she aims to make the garden as bee and butterfly friendly as possible.

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