Conkers, also known as Horse Chestnuts, are the round, dark brown nut of the Horse Chestnut tree. These nuts are encased in a spiky green shell that falls to the ground in the autumn, opening on impact and releasing the conkers inside.
While children pick up horse chestnuts ready for games of conkers, they should be reminded never to eat them as they are toxic. But are these seeds also poisonous to dogs?
Yes, conkers are poisonous to dogs if they are chewed or eaten. In fact, all parts of the horse chestnut plant are poisonous, including the leaves.
Horse chestnut trees and conkers contain a toxic chemical called aesculin which affects people and many animals, including dogs. There is no known antidote to counteract aesculin poisoning, meaning a vet can only give supportive treatment to help ease symptoms and give your dog the best chance of recovery.
Aesculin is a neurotoxin, meaning it damages the nerve tissues. If eaten in large quantities, aesculin can also be hemolytic, where it will rupture red blood cells. Both are incredibly serious and will make your dog very sick, so veterinary treatment must be given to your dog urgently.
It is a small mercy that horse chestnuts are meant to taste bad, which means it is uncommon for a dog to ingest large amounts. However, it won’t always stop a pooch from eating the conkers, and even ingesting a small amount can trigger serious illness.
Not only are conkers poisonous to dogs, but the nuts and the spiky shell can also cause damage and blockages in your dog’s gut if they are ingested. They also pose a significant choking hazard.
If you suspect your dog has consumed conkers or any part of a horse chestnut tree you should contact your vet promptly for advice.
Horse Chestnut trees are common throughout the UK, particularly in parks and woodland. The nuts ripen throughout the summer and fall to the ground in autumn. Conkers usually fall from September onwards, however, if it has been a long hot summer, they can sometimes fall as early as August.
Spying the first ripe conker on the ground is an important marker in nature’s calendar and is being recorded to help monitor the effects of climate change. This is because earlier and sunny spring and summer seasons will make large crops of big conkers that will fall unseasonably early, whereas short and wet summers make for smaller fruits and lower yield.
Conkers can look similar to a sweet chestnut. However, horse chestnuts are larger, rounder, and dark brown. The horse chestnut’s green casing has thicker, shorter spikes which are more spaced out. Whereas the spikes on a sweet chestnut casing are tightly packed together and very thin, while the chestnut itself is small and often flat on one side. Sweet chestnuts are round on top but taper to a point at the bottom.
Unlike conkers, sweet chestnuts are non-toxic for humans and dogs. Meanwhile, horse chestnuts are toxic, making it important to be able to tell the difference.
If your dog has consumed conkers and has been poisoned they may show any of these symptoms:
Abdominal pain & discomfort
Muscle twitching & spasms
Respiratory changes (Such as difficulty breathing.)
In milder cases, your dog may be restless with vomiting and diarrhoea. Eating conkers can cause gastrointestinal stress which can lead to illness such as gastroenteritis and cause vomiting and diarrhoea. These symptoms are more associated with gastrointestinal upset than with poisoning.
More serious cases of poisoning require a dog to have ingested a significant amount of conkers, and they are uncommon. In these cases, your dog may go into toxic shock where they appear depressed and struggle to move. Their muscles will be rigid and may even spasm, and the dog will develop a fever. Toxic shock occurs quickly, within a few hours of consuming the conkers. In some rare cases, a dog can go into respiratory paralysis and die.
Regardless of if your dog ate a single conker or a few, they may show signs of illness within a few hours of consumption. However, it often takes several days before a dog shows any symptoms. This means that your dog could fall ill anywhere between 1 to 6 hours of eating a conker, or anywhere up to 2 days.
If your dog has eaten any conkers you should keep a close eye on your pet for signs of illness and contact your vet as soon as possible. If you have seen your dog eating them, try to remember how many they have eaten and share this information with your vet. It’s important to give them an estimate of how many conkers your dog has consumed and at what time they ate them.
It usually takes consuming several horse chestnuts to cause poisoning, but this will vary on the size of your dog. If you have a smaller breed like a terrier, they can be poisoned by a smaller volume of aesculin compared to a larger breed like a Rottweiler. You should call your vet regardless of how many conkers your dog has eaten.
It is important to keep a close eye on your dog to monitor their behaviour and symptoms and contact the vest promptly so they can assess your dog’s condition and discuss necessary treatment.
There is no known antidote for aesculin poisoning, so veterinary treatment for a dog that has fallen ill is supportive. The care given will be to ease symptoms, minimise the toxin in their system, and to relieve their pain and help their body recover from the poisoning.
Treatment for a dog suffering from conker poisoning will involve rehydrating them using an intravenous drip to recover lost fluids, particularly if they have had vomiting or diarrhoea.
The vet will need to ensure that there are no traces of the conker left in your dog’s system. This is both to prevent further poisoning and to try and stop it from causing blockages in the stomach or intestinal tract. To do this, your dog may be given medication to induce vomiting. If your dog has only eaten a small amount and not yet vomited, you may be advised on how to safely induce vomiting yourself at home.
In serious cases where a dog has ingested significant quantities of conkers, or some remain stuck, they will have to undergo gastric lavage or surgery to remove the remaining nuts. Gastric lavage requires anaesthetising the dog and using a sterilised tube that is inserted into the stomach. Water is flooded into the stomach and drained out the tube, flushing out anything left in the dog’s stomach.
If there are any remains of conkers that cannot be removed naturally or using these methods, your dog may have to undergo surgery to remove the conker to prevent further obstruction.
Your dog will be given any medication needed to relieve pain, settle their digestive tract, and prevent any further vomiting. Once your pup is home again, they will need plenty of rest to recover and access to freshwater to keep them hydrated. As with many illnesses affecting their stomach it may be advised that your dog undergo a short period of starvation until their gut has settled, followed by small but highly digestible meals of high-quality nutrition to help heal and protect their gut.
Regardless of the severity of poisoning, provided the conker is removed from your dog’s system you might find they recover from the acute gastrointestinal symptoms within a day.
Even in more severe cases of conker poisoning, as long as your pooch received adequate treatment promptly, they should make a full recovery within a few days.
However, there are rare cases where conker poisoning proves fatal.
As with many illnesses, your pooch may face over their lifetime, prevention is often easier, more natural, and safer than the cure.
If you are concerned that your dog may try to eat conkers, you should walk them in areas away from any horse chestnut trees where they are unlikely to find any conkers on the ground. Keep your dog on the lead so you can keep a close eye on them and stop them wandering away to forage. You also should always supervise your dog while walking in case they try to eat something they shouldn’t, be that a stone, a conker, or another dog’s stool.
If your pup picks something up, give them the “leave” or “drop” command right away. Should they refuse to let go of what they picked up, you will need to remove it from their mouth yourself.
If your dog has a habit of foraging and trying to eat things they shouldn’t when out on walks, it might be worthwhile muzzle training them. Properly fitted muzzles do not harm a dog and they can still breathe normally and communicate, but it will prevent them from eating anything that they shouldn’t.