Autumn Dangers for Dogs

Nothing beats an Autumn's day dog walk. We all love breathing in that cool, fresh air whilst kicking through fallen leaves with our canine companions. But amidst its colourful beauty, Autumn can pose health threats to dogs.


Acorns are the nuts of the oak tree. Like conkers, they fall from the trees in late September-early October. Acorns contain tannins which are toxic to dogs. If ingested, they cause stomach upsets and can also cause liver and kidney damage.
Affected dogs show signs such as:

  • Vomiting
  • Diarrhoea
  • Lethargy
  • Abdominal pain
  • Although too small to cause an intestinal obstruction in most dogs, acorns can be a choking hazard.


Conkers are the seeds of the horse chestnut tree that usually fall from late September-early October. They contain a chemical called aesculin, which is toxic to dogs if ingested.

Luckily, conkers have a very bitter taste and so cases of poisoning are rare. However, some dogs, especially puppies, might eat enough to make them unwell. Dogs may also inadvertently swallow conkers if playing with, or carrying them in their mouths.

Common signs of toxicity include:

  • Salivating
  • Retching or vomiting
  • Diarrhoea
  • Abdominal pain
  • In some cases, affected dogs can show neurological symptoms. As well as causing toxicity, conkers can also cause an intestinal blockage.

Fallen leaves and fermenting fruit

Piles of leaves and dropped fruit can contain heavy growths of bacteria and mould. Rotting fruit can also produce natural alcohol compounds. If ingested directly, or licked from their coat after a walk, these can make dogs very unwell.

Seasonal canine illness

Seasonal canine illness (SCI) is a relatively newly described condition. It has been reported to occur in some areas of the UK between August and November. The cause is yet unknown and research is ongoing. It has been suggested that harvest mites might play a role.

Dogs affected by SCI usually become sick within 72 hours of walking in woodland. Signs include:

  • Loss of appetite
  • Vomiting
  • Diarrhoea
  • Abdominal pain
  • Muscle tremors

Without early treatment, seasonal canine illness can be fatal.

Harvest mites

Harvest mites are tiny orange insects. They can be found near the ears, between the toes or in the armpits of dogs which have been in long grass or dense foliage. The mites cause intense discomfort and itching and can drive your dog crazy.


Fireworks are around a lot from Autumn to New Year, and frighten many dogs. They are a common cause of noise phobias in dogs with RSPCA data suggesting that over 60% of dogs show marked signs of distress when exposed to firework displays.

Mushrooms, toadstools and berries

Some species of wild mushroom and toadstool are toxic to dogs. They cause vomiting, diarrhoea, weakness, collapse, neurological signs and organ failure. Some berries can be poisonous too.

Rodent poison

Colder weather can unfortunately encourage pests indoors, meaning it is more common for us to see cases of rat and mouse bait poisoning in dogs in the Autumn and winter months. The level of toxicity and risk depends on the type and amount of chemical ingested.

Chocolate and sweets

Thanks to Halloween leftovers and early Christmas purchases, there's often an abundance of chocolate and sweets in the house in the Autumn and Winter months. Chocolate contains a chemical called theobromine, a stimulant (like caffeine) that is poisonous to dogs. Sweets often contain Xylitol, an artificial sweetener which is also toxic to dogs.

Plant bulbs

During Autumn, many people start to plant bulbs in the garden ready for spring. Some of these, including lillies and daffodils, can be toxic to dogs.

To keep your dog safe this Autumn:

  • Do not encourage your dog to play with conkers or acorns. If you think they might have eaten one, give us a call immediately.
  • Avoid letting dogs eat, roll in or play with rotting leaves or fruit. If their coats or legs become contaminated, rinse them after their walk.
  • Do not let your dog eat mushrooms, toadstools or berries.
  • Be on the lookout for reports of seasonal canine illness in your area.
  • Speak to us about products that can be used to prevent and/or treat harvest mite infestation.
  • During times when you expect fireworks - keep your dog in during the hours of darkness. Be proactive in getting your puppy used to firework sounds. If your dog is usually severely affected by fireworks, give us a call as we can put you in touch with a behaviourist and/or suggest some medications to help.
  • When trying to get rid of rodent pests, use pet safe products if possible. Ensure any poisons you put down are out of reach of any dogs in the house. If you suspect a dog has eaten rodent poison, contact us immediately for advice.
  • Keep all sweets and chocolate out of your dogs’ reach. If you think they might have eaten chocolate or sweets containing Xylitol sweetener, contact us for advice.
  • Do not allow your dog to eat or play with plant bulbs which may be toxic.

As always, if you have any concerns please speak to a vet.

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