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Toxic to dogs

Dogs are full (though non-voting) members of our families, so it’s easy to treat them as any other member of the family. Yet it’s all too easy to kill them with kindness.

Be careful with what your dog eats. Many common foods that we eat, and would be tempted to share with our dogs, can harm and even kill dogs. For example, did you know that chocolate is deadly to dogs? Or artificial sweeteners? Or onions, macadamias, mushrooms or alcoholic drinks?

Here is a list of foodstuffs to keep out of Fido’s reach.

Chocolate: Theobromine and caffeine, both present in high concentrations in chocolate, can cause problems for dogs. A small amount of chocolate can cause excitability in a dog. Prompt treatment by a vet, such as induction of vomiting followed by administration of activated charcoal and a laxative, will usually prevent further problems. But the darker the chocolate, the more theobromine and caffeine it has in it, so the easier it is for a dog to ingest a toxic amount. Theobromine is fatal at doses of 250 mg per kg of body weight or above. Dark cooking chocolate contains about 16 mg per gram. A dog weighing 30 kg would need to ingest 7.5 g of theobromine, which is found in less than 500 g of dark chocolate, to be at risk of death by chocolate. If you have used cocoa bean hulls as mulch anywhere, and your dog is keen to eat everything, keep him away from the mulch.

Grapes, sultanas and raisins: For reasons no one has yet discovered, grapes, either fresh or dried, have poisoned some dogs. An intake of as little as 3 g of raisins per kg of dog, or 90 g for our putative 30 kg dog, has proven toxic. Symptoms include vomiting, diarrhoea, lack of appetite, lethargy and abdominal pain, and can progress to kidney failure. If you use sultanas as rewards for good behaviour, keep them to half a dozen. And watch out if you leave a bowl of grapes on the table.

Onions: Almost a staple of the Western diet, onions contain sulphur-based chemicals called thiosulfates. In moderate amounts, these chemicals can promote health. But in high amounts, they can cause haemolytic anaemia, in which red blood cells burst. Garlic, long known to have disease-fighting abilities, also contains thiosulfates. The toxic dose is not known, but symptoms include vomiting, diarrhoea, anaemia, discoloured urine (due to the burst red blood cells), weakness, depression and lethargy, liver damage, allergic reactions, asthma attacks and contact dermatitis. So be careful with the leftover spaghetti sauce.

Macadamias: The toxic component is not known, but as little as 2 g of nuts per kg of dog (60 g for a 30 kg dog) has proven toxic. Symptoms can appear after about 3 hours, and include rear-end weakness, tremors, lethargy, depression, vomiting, diarrhoea and high temperature. Dogs recover within 12 to 36 hours.

Wild mushrooms: Dogs that are inquisitive and like to nibble at whatever they find can ingest wild mushrooms, some of which are poisonous. Symptoms can include vomiting, diarrhoea, abdominal pain, lethargy, jaundice, seizures, coma, drooling, loss of coordination, liver failure, kidney failure and even death. The symptoms, treatment and outcome all depend on the type of mushroom.

Alcohol: This is a poison that happens to produce pleasant effects in humans at moderate doses. In dogs, though, it can prove fatal. Symptoms of poisoning resemble those seen in humans—wobbly gait, vomiting and disorientation—but can extend to heart arrhythmias and arrest. If you have had a party, all the glasses are empty and your dog looks tipsy, take him to the vet.

And more: The list goes on, and includes antifreeze, rat poison, vitamin supplements, cane toads, farm chemicals, cooked bones, cat food (too much protein), liver, peach pits (contain cyanide), rhubarb leaves, raw eggs, raw fish, coffee grounds, bread dough and yeast.

Further information

There is plenty of advice on the Web about foods that are toxic to dogs (and other pets). Do a search on “dogs poisonous foods” and you will find thousands of references.