The Dangers Of Rotten Apples For Dogs -
The Dangers Of Rotten Apples For Dogs

The Dangers Of Rotten Apples For Dogs

Most dogs love snacking on contraband they find on walks or in your yard. But what happens if you see your dog eating rotten apples off the ground? How bad are rotten apples for dogs?

Is Eating Rotten Apples Bad For Dogs?

If your dog eats fallen apples, they could have been rotting on the ground for days or even weeks. One result may be typical symptoms of overindulgence … such as abdominal pain or other upset stomach symptoms like vomiting or diarrhea.

Treat this as you would any case of diarrhea. The best approach in adult dogs (don’t fast puppies) is usually to fast your dog for a day, giving probiotics, plus gut-healing herbs like slippery elm or marshmallow root. When you reintroduce food, give a bland diet for a couple of days to let your dog’s digestive system recover.

RELATED: How to manage diarrhea in dogs …

Mycotoxin Poisoning

A more serious risk of eating rotten apples is the  possibility of mycotoxin poisoning from moldy apples. Veterinarians report that this happens most when dogs get into compost or other garbage with moldy food. Tremorgenic mycotoxins are metabolites produced by fungi species that can grow on fruits, refuse and compost, as well as meat, cereals, nuts, cheese, eggs, and processed/refrigerated foods (1). These are dangerous molds that can cause toxicity to the brain, with severe symptoms of vomiting followed by muscle tremors or seizures and other neurologic signs.

These symptoms need an emergency vet visit. Depending on how long it’s been since your dog ate the mold, treatment may include induced vomiting, activated charcoal. Gastric lavage or IV fluids may also be given, as well as medications to manage seizures or other serious symptoms. .

So, even if you don’t have apple trees, make sure your dog can’t get into a compost pile or garbage bin with moldy apples or other food in it. 

Ethanol Poisoning

There’s another serious risk if your dog really eats a lot of rotten apples. And that is the risk of ethanol poisoning … which is alcohol toxicity. According to a French case report, one dog died of ethanol poisoning after eating a massive amount of rotten apples (2). This isn’t common. But ethanol poisoning in dogs can happen in other ways too. 

Dogs most often get ethanol poisoning from eating raw bread dough (3), or drinking alcoholic beverages or commercial products that contain alcohol.  These include rubbing alcohols, mouthwash, perfumes, and paints. Dogs can absorb ethanol through the skin, so some cases of ethanol poisoning have been caused overspraying pets with alcohol-based flea sprays.

Symptoms of ethanol poisoning include repeated vomiting, ataxia, tremors and dehydration. If your dog shows these signs, take him to the veterinarian immediately (even if he hasn’t been eating rotten apples). Veterinary treatment man include induced vomiting, and fluids to encourage alcohol elimination.

As you can see, it’s safest to prevent your dog from chowing down on a lot of rotten apples under the trees. 

Other Risks Of Apples For Dogs

Apples are generally good for dogs and can be a nutritious snack … but there are a couple of other ways apples could be bad for your dog. 

Pesticides In Apples

First, apples may contain pesticides, especially on the skin if they’ve been sprayed. In fact, apples rank 5th on the Environmental Working Group’s “Dirty Dozen” list of pesticides in produce.

This means you should always buy organic apples so you don’t have to worry about toxic pesticides.  

Try to prevent your dog from getting access to conventionally grown apples that may have contain pesticides … even if the apples aren’t rotten. 

Cyanide In Apple Seeds

You might also have heard that apple seeds contain cyanide. It’s true that cyanide can be toxic to your furry friend (and you!) in large enough quantities. But, as veterinarian Dr Marty Becker says, “the amount of cyanide within a few seeds is so minimal that it’s really not a concern.”

Also, the seeds would have to be crushed to release the cyanide, and most dogs don’t chew enough for that to happen. 

Unless you live in an apple orchard and your dog can gorge on the fruit all day, you needn’t worry about cyanide poisoning. If you have a very small dog and want peace of mind, don’t feed the apple core, or remove the seeds before giving apple to your dog.

Are Fermented Apples Bad For Dogs?

Are fermented apples considered rotten? No … in fact fermented apples can be very healthy for your dog. There’s a difference between rotten apples that have been lying on the ground for weeks and apples that you’ve intentionally prepared to “rot” in a safe place. Those are fermented apples, and they can have some benefits for your dog’s health.

Health Benefits Of  Fermented Apples

Fermentation is a natural process in which microorganisms like yeast and bacteria break down food molecules into other forms, such as acids and alcohol. The good bacteria, or probiotics, involved in this process are great for intestinal health. And apples also contain pectin, which has prebiotic effects (4). Prebiotics provide food for the good bacteria in your dog’s gut. 

After reading about ethanol poisoning from rotten apples, you may wonder if fermentation could lead to alcohol poisoning. But the likelihood of this happening to your dog is very low. Give fermented apples in moderation and your dog will reap their health benefits. Here’s how to safely make your own fermented apples. 

Fermented Apple Recipe

You can ferment your own apples with just a few simple ingredients: a glass jar, organic apples, salt, lemon, and filtered water.

  1. Combine 1 lemon (juiced and zested) with a teaspoon of sea salt and 4 cups of clean, filtered water in a pot, over medium heat until it’s almost simmering. Make sure the salt is dissolved!
  2. Slice the top off one of the apples and set it aside.
  3. Wash, core, and thinly slice 3 medium-sized organic apples into small pieces. Place them in the jar with about an inch of room at the top.
  4. Pour the water and lemon mixture into the jar until the apples are covered in the liquid.
  5. Use the top of the apple you set aside to plug the jar so all the apple pieces are submerged, and cover the jar with a cheesecloth.
  6. Store the jar at room temperature for 3 to 4 days to allow it to ferment. You should notice the brine bubbling, which is a sign that it’s working!
  7. Taste the apples after 4 days ­– they should be tangy. If they don’t seem fermented yet, you can leave them for another couple of days, checking each day.
  8. Once done, store the jar in the fridge to stop the fermentation process. They should keep for a couple of months so you can give your dog a few teaspoons per day.

Simply mix the apples with his food or give them as is for a snack. And there you have your very own homemade pre- and probiotic! 

In summary, you’ll want to avoid your dog eating a lot of apples that have been lying on the ground. Apples can be very healthy for dogs, but not when they’re moldy or rotten. 


  1. Kirsten Waratuke, DVM, DABT. Tremorgenic Mycotoxin Intoxication In Dogs. Today’s Veterinary Practice.May/June 2017. 
  2. Kammerer, M. et al. Ethanol toxicosis from the ingestion of rotten apples by a dog. Vet Hum Toxicol.2001; 43(6): 349-50.
  3. Sharon M. Gwaltney-Brant DVM, PhD, DABVT, DABT. Bread dough toxicosis in animals. Merck Veterinary Manual. July 2021. 
  4. Chung WSF, Meijerink M, Zeuner B, Holck J, Louis P, Meyer AS, Wells JM, Flint HJ, Duncan SH. Prebiotic potential of pectin and pectic oligosaccharides to promote anti-inflammatory commensal bacteria in the human colon. FEMS Microbiol Ecol. 2017 Nov 1;93(11).