By Margot Hunter of Dunedin Vets

THE festive period is upon us again – a great time for everyone to enjoy themselves.

This is true for our pets as well. Most cats and dogs love to see the bright lights and decorations. Kittens are particularly adept at scaling Christmas trees and pulling down tinsel. Pups love to tear at wrapping.

Please be aware that there are some everyday substances which are probably more likely to be around at this time of year that can be extremely toxic to your pet. Many owners are unaware of the potential danger to their pet.

Every year at Dunedin Vets we treat many pets which have been inadvertently poisoned and see some very distressed owners who feel so upset that they were unaware of the hazardous substance.


Most owners are aware that chocolate is toxic to pets and chocolate poisoning in dogs is the most common poisoning we see. Dogs are more likely to be involved than cats, who are less likely to eat chocolate as its flavour is less appealing to them. Be aware, though, of some gourmet chocolates with sea salt which are attractive to cats.

Chocolate contains a powerful stimulant called theobromine. This is a similar substance to caffeine found in coffee and tea. Just as caffeine is a stimulant, causing your heart to race and beat strongly, theobromine causes this to a much greater degree.

The first signs that your dog has chocolate poisoning (apart from noticing torn wrappers), are vomiting and diarrhoea. If this occurs they will probably feel much better and recover and not go on to suffer the full effects of the theobromine.

If the dog digests the chocolate then the more serious signs occur. These include hyperactivity, high temperature and blood pressure, a fast heart rate and heartbeat irregularities. Some of these signs can occur within a few minutes.

The darker the chocolate, the greater the concentration of theobromine and therefore the more rapid onset of serious signs. Remember that chocolate cake and chocolate sweets are harmful too, not just bars of chocolate. If you know your pet has eaten chocolate, contact your vet immediately.

This is exactly what Mrs Isabella Patterson with her pet Yorkshire terrier Dougal did. Dougal had enjoyed a chocolate feast, eating a substantial amount of 80 per cent chocolate. Dougal usually attends our Dunbar surgery but he was rushed to our main Tranent surgery for emergency treatment. On arrival, he was panting and had a rapid heart rate and he had vomited once but was given an injection to induce further vomiting. Soon, little Dougal had emptied his stomach of the chocolate. He looked very bedraggled and wanted lots of cuddles. He was given activated charcoal orally which helps to absorb any remaining toxic substance.

Fortunately, Dougal soon made a full recovery, but his taste for anything chocolate still remains.

Vine fruits (e.g. grapes, currants and raisins)

Fresh grapes and their dried varieties are toxic to pets even in small quantities. During the festive period, think about all the places where these fruits can be found: in the Christmas cake, Christmas pudding, mince meat pies, and black bun. The cooking process does not reduce the chance of poisoning.

These fruits can initially cause gastro-intestinal upsets such as vomiting and diarrhoea. However, if the grapes are digested then a toxin enters the body which can cause kidney failure. This is likely to occur a few days after the initial ingestion of the food. Your pet is likely to be quiet and lethargic. They may be unwilling to eat. They may be drinking lots or not at all.

If you suspect your pet has eaten grapes or similar and is showing any of these signs then take them to your vet immediately. Your pet is likely to be given intravenous fluids and have a blood sample taken to check how their kidneys are working. It is likely that your pet will need to be hospitalised for a few days on fluids and given supportive treatment to help the kidneys.

Bear in mind grapes can be a choking hazard for small pets.

Holly, ivy and mistletoe

Holly, ivy and mistletoe are Christmas staples but all are toxic to our pets. The toxins they contain have severe effects on the body’s nervous system.

Holly ingestion can cause vomiting but, if digested and the poisons absorbed into the body, nerve problems can occur including loss of balance and wobbliness, tremors and even fits and seizures.

The whole ivy plant is toxic if eaten but the leaves and berries are particularly so.

A species, which is commonly poisoned by ivy is the rabbit. They seem especially attracted to its leaves. Initially the rabbit may show signs of lethargy, diarrhoea and reluctance to eat. As the toxins are absorbed, neurological problems such as twitching, collapse, fitting and paralysis can occur.

Mistletoe berries are toxic. Puppies can often chew them. The juice of the berries is an irritant and can cause sores and ulcers in the mouth. If the berries are swallowed and the toxin absorbed, seizures and death can occur. Only a few berries are enough to be lethal.

If you see your pet eating any of these plants, remove any traces from the mouth. Try to make your pet drink, especially in the case of mistletoe. Take your pet to your vet as soon as possible. If you do not know what plant they have been eating, take along a piece for the vet to see. Your pet is likely to be admitted for intravenous fluids and medication to stop seizures.

Onions, garlic, etc

Onions and other members of the allium family can be toxic to your pets. Remember at this time of year, onions in soup and garlic in sauces and seasonings are still potentially toxic. The alliums contain the chemical disulphide, which damages the red blood cells in domestic animals. Toxicity can occur by ingesting a lot of onion at once or taking in a small quantity over a period of time. Dogs like cooked onions so be aware of this if you have prepared caramelised onions or similar.

The toxic chemical causes red blood cells to break up, resulting in anaemia and an inability to carry oxygen around the body.

Signs that your pet may have onion poisoning include weakness, depression and lethargy. They may be panting and breathless. They may have pale gums and a weak pulse, or collapse.

Contact your vet immediately if you suspect they have eaten onions. Your vet will blood sample your pet to check the degree and extent of the anaemia and red blood cell damage. Your pet will be given intravenous fluids and may even require a blood transfusion. Most cases of onion poisoning recover but intensive veterinary care and treatment is required.

Macadamia nuts

Macadamia nuts are just the right size for causing blockages in cats. They are also toxic to both cats and dogs. Within a few hours of ingesting the nuts, lethargy, vomiting and an increase in body temperature can occur. This can progress as the nut toxin affects different organs. There may be neurological signs with weakness, wobbliness or tremors. There may be lameness and stiff joints. Eventually the animal may collapse.

Again, contact your vet if you know your pet has ingested a macadamia nut. They will require supportive treatment.

In cats, where the nut has caused an obstruction, surgery may be required to remove the offending item from the intestines.