Toxic Dog Food


There are a number of foods which people eat which are toxic to dogs. Depending on the amount eaten, they can make a dog ill or even result in the dog's death. Examples are:

The amount of the above items which a dog can consume without becoming ill (or dying) varies from dog to dog. Key factors include the dog's size, health and individual sensitivity.


Chocolate is poisonous to dogs, both in its pure form and also in diluted forms (e.g. milk chocolate). The specific chocolate chemical that is toxic is theobromine, which is a cardiac stimulant and a diuretic. Fortunately, this compound is not present in dog chocolate (which you buy at a dog food store), but it is present in the various types of chocolate which you can purchase at a human food store.

The symptoms of a chocolate overdose may include the following:

  • May become excited or hyperactive
  • May urinate more than normal and be unusually thirsty (this is due to the diuretic effect)
  • May vomit or have diarrhoea
  • Heart rate may be elevated or irregular

A dog may appear fine after eating chocolate. However, it is quite possible for a dog not to display symptoms for some hours and yet die within a day of a chocolate overdose. Consequently, if your dog has eaten chocolate, it would be advisable to see veterinary attention at the earliest point possible.

The amount of the topic chemical  (theobromine) depends on the type of chocolate. Cocoa powder and cooking chocolate have the most concentrated levels; followed by dark chocolate and semi-sweet chocolate, with milk chocolate being the least dangerous.

For chocolate, 50% of adult healthy dogs will die from consuming:

  • 7 g. of baker's chocolate per kg. of dog. This equates to 70g for a 10kg dog or 2 ounces for a 18 pound dog.
  • 20 g of semi-sweet chocolate per kg. of dog. This equates to 200g for a 10kg dog or 5 ounces for a 15 pound dog.
  • 60g of milk chocolate per kg of dog. This equates to 600g for a 10kg dog or 1 pound for a 16 pound dog.
  • However, symptoms of toxic poisoning can appear at one-tenth of these levels.

Onions and Garlic

Onions contain thiosulphate, which is toxic to dogs. This chemical is also present in other members of the onion family (notably Garlic). An overdose results in the dog's red blood cells bursting (haemolytic anaemia).


The symptoms may include the following:

  • May vomit
  • May have diarrhoea
  • May have reduced interest or no interest in food
  • May be dull and weak
  • Urine may be pinkish (the colour is from the burst blood cells)
  • May be short of breath (due to loss of red blood cells)

The symptoms may not appear until some days after the onion has been eaten.


Onions (and Garlic) are poisonous in all forms: raw, cooked, dehydrated. If you feed your dog 'table scraps', be aware that onion is often added to restaurant and fast foods (e.g. pizza) even if not requested. It is also added to various products (e.g. baby food) in powdered form, so may not be visible.


That being said, onions and garlic appear to be a serious health risk only in large amounts. Some research suggests that the deadly level for a dog is about 50g of onion per kg of dog, which equates to half a kilogram for a 10 kilogram dog, consumed either at one time or over a few days. Research indicates that garlic is less toxic than onion.


Despite the dangers of large quantities of onion, many people believe that in small quantities it is beneficial. It is added to many dog foods and is included in many 'home made' dog food recipes. Raw garlic is also used by some dog owners as a natural flea repellent (not necessarily 100% effective, but useful).


We hope there will be more research in order to confirm the effects of onion (and onion family) when consumed in small quantities.


Macadamia Nuts

Macadamia nuts are toxic to dogs, although the exact chemical which is responsible has not been identified. Symptoms may include:

  • Tremor of skeletal muscles
  • Weakness or paralysis in hindquarters
  • Panting
  • Swollen limbs. Pain when these limbs are manipulated

The effects of macadamia nuts is not well researched. Without further research, it is unknown whether the effects of eating these nuts extend beyond short-term experience of the symptoms listed above. The small amount of research available suggests that as little as 6 nuts can result in the above symptoms.

Fruit seeds

The seeds of various fruits can be dangerous. Consequently, if feeding fruits to dogs, it is a good general precaution to remove the seeds.


Examples of poisonous seeds include those of apples, apricots, peaches, pears and plums.


There are many items which are toxic to people, which are also toxic to animals. The fact that we consume them at our own risk does not mean we should feed them to our dogs. One should also keep in mind that a dog (especially a small dog) may have much lower resistance than ourselves. In particular:

  • Alcohol. Some dogs will happily consume more than is good for them (or even become alcoholic). As in ourselves, excessive consumption can result in permanent damage and early death.
  • Cigarettes, tobacco, cigars. Various short-term and long-term effects.
  • Coffee grounds, coffee beans, tea.  The caffeine present in these items is unsuitable for dogs.

If one would not eat something oneself, one should consider carefully if one should feed it to a dog. It is true that a dog's digestive system can withstand many things that would be dangerous to a person (this is partly due to the high acid levels in a dog's stomach). Examples of unsuitable foods that people have fed to dogs (with unfortunate results) include:

  • hops
  • mouldy or spoiled foods
  • potato peelings or green potatoes
  • rhubarb leaves
  • tomato leaves and stems

Grapes, raisons and avocados are known to be toxic to dogs. Broccoli is also reported to be toxic (in large quantities)

Toxic Levels

The amount of the above foods which can be eaten without serious injury or death varies greatly from dog to dog. In general, a large dog can eat more than a small dog and a healthy dog more than an unhealthy one. Very young or very olds dogs may be more susceptible to many toxins. A dog with certain medical conditions (which may or may not be known) may be more affected. Finally, there is simply individual variations.


Some toxins can also be cumulative. A moderate amount eaten once may not be overly dangerous, but the same amount fed every day for several days in a row may be. Likewise, a non-fatal amount of one toxin combined with a non-fatal amount of another could be deadly.


Consequently, it is extremely difficult to say exactly what amount can be eaten and survived, or what amount can be eaten with permanent injury (e.g. permanent damage to internal organs). In general, providing medical treatment in a timely fashion greatly reduce the possible effects.