Acorns Can Pose a Danger to Dogs


Not that anyone asked, but my favorite tree in the whole world is the oak tree. We have dozens of species of oaks in California, and where I grew up, in the great Sacramento Valley, the Valley Oak (Quercus lobata) is the most ubiquitous and also the largest oak tree around. They live to be hundreds of years old and grow into massive, photogenic shapes. When my husband and I bought the property where we have lived for the past (almost) three years, one of the key selling points was the magnificent hundred-year-old Valley Oak that stands in front of the house, and several other smaller Valley Oaks sprinkled around the property, along with some lesser oak varieties, the Blue Oak and the Live Oak.

Here’s the down side of living with oak trees, one that I never fully appreciated until now: acorns. So. Many. Acorns. And while all the oak trees are producing them, the Valley Oak makes some of the largest ones; they exceed the size of a standard tube of lip balm. Their distinctive “caps”, too, are a hazard. When they separate from the acorn, they become a separate large, hard, marble-shaped hazard.

The Valley Oak in our front yard: Magnificent and a prolific producer of acorns

Acorns underfoot on the lawn. (“Ow! OW!”)

Acorns getting mowed by the mower (turning the mower into a dangerous, projectile-throwing machine).

And worst of all: Dogs chewing on and (sometimes) eating the acorns.

California kids grow up with the information that the native indigenous people in California harvested the acorns and made them a staple of their diet – and every California kid who lives near an oak tree tries to reenact this. You gather acorns, peel off the skin to expose what appears to be a big, delicious nut, and find some rocks capable of grinding the nuts into a coarse flour. The goal is to then add some water and use your hands to mix the flour and water into a dough and try to make a tortilla. At some point in the process, you dip your finger into the flour and lick it, or take a little bite of the dough, and – ACK! Blech! It’s bitter!

When California kids get a little older, they learn that acorns are full of bitter tannins, and that the native people used to leach the flour with water, sometimes many times, to remove the bitter substance and make the acorns safe to eat.

And, as vet-bill-paying adults, we learn that in addition to being bitter-tasting, these tannins can be toxic to humans, horses, and dogs. Shoot!

Tannins in acorns can be toxic to dogs

I know several people whose dogs get sort of addicted to chewing the bitter-tasting nuts and end up with an extremely upset stomach – and in severe cases, kidney failure and death. A dog who becomes inappetent after eating acorns requires immediate veterinary care. My sister had a little dog who, at least once a year, would require a vet visit after sneaking a few acorns. She liked them after it had rained a time or two in the fall, when the nuts have gotten soaked with rainwater and fermented slightly – which seemed to increase their toxicity.

It took me about 10 minutes to collect this bucketful of nuts and caps.

Despite the wealth of nuts littering my property in the fall, neither of my dogs has been interested in picking them up or chewing them, even speculatively, and up until now, neither have any of my foster dogs. That is, until my most recent foster dog arrived. I have to keep a very close eye on Coco, who has become inexplicably drawn to chewing on the acorns, to the extent that I basically can’t have her out of my sight on my fenced, two-acre property. Wah!

Like my sister’s dog from years ago, Coco is (thankfully) uninterested in the dry ones that cover most of my property, and is mostly drawn to the ones that have been soaked by the sprinklers on my front lawn. While this is quite a lot, given the GINORMOUS Valley Oak, the pride of our property, at least it’s just those. So it’s my new evening hobby: hanging out on the front lawn in the evenings with my dogs, throwing the ball for Woody, watching Woody and Coco wrestle, watching Otto watch for feral cats and squirrels … and picking up acorns from the lawn, and dumping them in our “green waste” barrel. I probably have a few more weeks to enjoy this new hobby before the tree’s supply is done and I can relax again.

Have you ever had trouble with an acorn-eating dog? Spread the word about this danger.


  1. I had a Ridgeback who loved acorns. We used to tell him if he didn’t watch out he’d end up with an oak tree growing in his tummy. I did not know they were toxic and I feel blessed he never had a stomach issue and lived to a ripe old age. He didn’t eat a lot of them, usually one or two and then stopped.

    Thanks for the advice to add to my list of no-nos for pups.

  2. Perhaps this is the reason that my newest rescue has some pretty gross diarrhea not too long after she got here. I have a huge oak tree in my back yard that has become quite prolific in acorns the past few years. I am used to occasionally have to pick a half shelf that has perfectly fit a paw pad, but never really worried about the dogs actually eating them. I think she learned her lesson though, and my other dog never messes with them.

  3. My little senior terrier mix dog, Connor, was chewing on something he found in a pile of oak leaves. Of course, I yelled, “drop it.” And he promptly swallowed it. The next morning he vomited twice. He never vomits. He didn’t want to eat for the rest of the day. Now I wonder if he had eaten an acorn. Thanks for the information. You’re amazing!

  4. I have an Oak tree in my back yard and my Aussie has been eating the Acorns. I will go and rake them up! She loves ALL nuts, but I don’t give her Pistachio because I read they are not good for dogs, however I worry because she loves them so much. Should I not give her any nuts? I worry she is missing something in her diet, but I feed her a good balanced commercial raw diet.

  5. My dachshund almost died. He carefully chews his food, and the acorns were no different. The vet thinks that’s why he got so sick. He required sub-cutaneous fluids for a week. I hadn’t met my husband yet. He doesn’t really know how bad it was and he thinks I’m overreacting.

  6. My chinook, Nell, loved acorns. One year as a young dog after we moved to house with an oak tree, she ate so many she had a rather significant gastric upset. She recovered but It was significant enough that she gave the habit up completely. My other chinook has never tried to eat them. I like to think his “big sis” warned him.

  7. Our house came with many oaks — a dozen or so that were more than 100 years old. For the first 10 years we lived there I didn’t know that the acorns were toxic to dogs. Every day I’d sweep the ones on the porch into a bucket because walking on them was like walking on ball bearings. The bucket got dumped into the compost heap. We never bothered with the ones in the yard — just too many of them. Our northern-breed dogs loved to crunch them up and swallow some. When I said something to my vet about acorns being toxic to sheep and asked about any problems with dogs, she said to move the dogs to an oak-free area or cut down the trees. Neither was possible, since we couldn’t let dogs out without close proximity to an oak tree. And we could not afford $2000 – $5000 per tree to remove them (somewhere around $40,000 total). We never had a problem with sick dogs. The dogs never didn’t eat breakfast or dinner unless they got a sock or leather work glove. (Husband learned the hard way about those! He was a slow learner, though.) We lived there for 14 years. I guess we really were lucky. And, I have always known that my self-sufficient-if-necessary northern breed dogs can eat almost anything!

  8. This article jiggled something in my memory about pigs eating acorns, even having them as a diet staple among feral or wild hogs, and exploited by pork farmers using natural feeds and forage for their herds. So I looked it up online and found a whole spectrum of opinion, from “acorns are toxic to pigs” to whole articles in ag journals about acorns as important components of pig diets. I wondered if pigs could be taken round to feast on seasonal acorns the way goats are to clear brush? Obviously, this is a bountiful harvestable foodstuff – and couldn’t the tannins be used for something, too, if one soaked one’s acorns? I hate to think of the waste – acorns are about 6% protein – and the harm to animals not equipped to utilize this source. Has anyone inquired about a way to get acorns away from curious canines and into beings and processes that could use this naturally abundant “crop”? Maybe starting with scientific studies of the varying levels of toxicity among different oak species?

  9. My 15 lb. dog swallowed one when he was little. I didn’t know this until he became frantic a few hours later and I had to rush him to the emergency room. The vet’s x-ray couldn’t tell what was happening, so gave him heavy sedation and pain killers. Five days later a football-shaped acorn came out in his poop, re-hydrated like a grape. His vet said really he should have been operated on because the acorn was too large to go down his digestive tract. Thank God it didn’t have a cap on it or it would have scraped its way all the way down.

  10. Good to know. My min pin, Brutus decided they were a delicacy, along with the 1/2 eaten doughnut and a few other choice finds. I watch him like a hawk, because if it’s remotely eatable he’s on it. That day he got thru a couple acorns with no upset, so all was well. Since then we walk on the other side of the street. I didn’t know they were toxic, they just seemed like something we didn’t need to mess with.

  11. Not exactly on point, but since I have horses and GSDs and live oaks (Florida), I had to add that my Tennessee Walker colicked and died from eating acorns. So, if some horses eat acorns and some dogs like horse poop, another possibility for trouble. We have to pay attention to what our animals pick up around our property, easier said than done! My favorite phrase is: “Leave It!”

  12. Our issue was a wild cherry tree, but we found a BRILLIANT solution: Shop-Vac! Did I look ridiculous vacuuming my back yard? Yes. Did the Shop-Vac pick up all the cherries, even the small ones that slid through the tines of the rake? Yes! Did my dogs stop grazing like deer? Yes. Totally worth it. Invest and look ridiculous 🙂

  13. Thank you. I’m wondering if my standard poodle and his diarrhea problem has been due to that? I live in Georgia and the acorns are falling like crazy! He has a very sensitive stomach anyway. So now I’m going to be making sure I walk the yard with him during this time

  14. We have several oak trees and our dogs have always ignored them until Levi, likewise, initially a foster. Levi is a 30lb blind mix of probably jrt and perhaps beagle.. We live on an acre so he has to wear a soft muzzle when he’s outside with our other dogs. One midnight emergency vet visit prompted by bloody vomit and I started clearing the yard of acorns. I use a pooper scooper. Levi is a little more than 1 year old. Thankfully acorn season is almost past. Picking up acorns now extends my daily yard pick up because with his will, he’ll find a way. I hope he outgrows eating anything and everything someday. Gotta love his persistence.

  15. My young Miniature Schnauzer ate some and got very ill. Thankfully, we got her through it but I now have to keep a close eye on her and the other dogs during acorn season. Our Basset Hound would be get them stuck in her paws and bring them inside sometimes so I have to be vigilant inside the house too. The schnauzer still tries to eat them although she’s now a senior with few teeth left.

  16. I have a 13 year old pit-bull mix we rescued as an adult. Her owner was incarcerated and she was left in the backyard to fend for herself until animal control picked her up. She was so skinny when we got her, you could count her ribs from a distance. We believe that’s what made her a scavenger. In any case, we realized this year that she was eating the acorns in our back yard, so we started picking them up. She had some pretty nasty poops, but no vet visits required. Thankfully. It’s good to know now that there is a real danger associated with them. We’ll remain vigilant. Thanks so much for the useful post.

  17. Hi Nancy, thanks for this article. I would like to add some very important information to it: WALNUTS and STRYCHNINE! We live in Lake County, home of walnuts and Pears. While we do have oak trees our dogs haven’t developed a taste for them (thankfully!) However, my female cattle dog mix Xena LOVES walnuts. And while the nuts themselves are not harmful their husks are! When the nuts drop they usually still have their green husk on which is full of a strychnine like poison. My vet tells me horror stories about the number of dogs she sees because of this. Liver and kidney damage can be the result of the worst of it. Xena tends to be chubby and it’s difficult to keep her weight down and as we know nuts are also full of fats that quickly add weight to her chubs. It’s a full time job to keep an eye on her and try to pick up all the nuts from several large walnut trees. They are our only source of shade and are lovely so I hate to even think about cutting them down. I felt this information may save a doggie life or two, so there you go. Thanks for all you do!

    • Thank you! I didn’t know about that! Today, we had a chimney sweep visiting and I was picking up acorns while he was working, and he mentioned that his business partner lost his dog to poisoning from eating green walnuts.

  18. My mini schnauzer loves to eat acorns. We try to pick them up during the day, but she always seems to find them. We have too many oak trees to keep our yard acorn free. She hasn’t gotten sick yet, but I do worry that she will.

  19. My miniature poodle, EmmieLou nearly died from chewing on acorns when she was 4 years old. It turns out that most of the acorns that have fallen in the rain are moldy and the aflatoxin is liver toxic. We have a red wood porch with a large oak tree overhead and a dog door leading to this porch. My baby presented with extreme lethargy and inappetence and I realized she was seriously ill. I rushed her to Sage Emergency in Concord, Ca not knowing she had been chewing on acorns. They determined that she was in liver failure with high liver enzymes in her serum and very low platelets. She received two transfusions and fluids for several days and they saved her 3K out of pocket. They are great there. The attending determined that she must have eaten an Aminita mushroom but I told him that was not possible since we had not walked in a month and her only access to the outside was the porch and not the yard— No mushrooms. I told him I had discovered chewed acorns with mold and that it must be Aflatoxin poisoning which gives the same liver damage as Aminita mushrooms. He scoffed at me and disregarded my observations. I insisted that this must be the case and said that it was important to note to help others and he still disregarded me. My Ph.D. from U.C. Berkeley in molecular bio research probably makes me more observant and intuitive than him so take it from me, moldy acorns on the ground can kill your dog. My Emmie’s liver made a full recovery and I now clear all the acorns from the porch.

  20. My weimaranera loves acorns, she mostly chews but sometimes eats them, she suffers with pancreatitus at least once a year am I right in thinking that this can be part of the cause, as well as bwinf intolerant of tii much fat in her diet.

  21. Several years ago one of my Bernese Mtn Dogs got massive bloody diarrhea from ingesting rotting acorns. She was treated at the emergency hospital and recovered quickly, but the lesson was learned. The acorns seem to be most enticing, and most toxic, when they start to rot. Whenever one of my grooming clients reports a dog with acute diarrhea around this time of year my first question is “Do you have oak trees in your yard?” Almost always the answer is “yes,” followed by “I never thought of that!” Thanks WDJ for spreading the word about this common and potentially deadly hazard.

  22. Oh my gosh! Thanks to everyone who suggested the Nut Wizard! (I think I bought an off-brand one.) It actually works better on the round acorn *caps* than the long, cylindrical acorns I have on my property; it only scoops up the long acorns if I roll across them lengthwise. But it’s better than crawling around on my hands and knees! video of the thing in action (and a cameo by Woody):