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10 Causes of Dogs Vomiting Undigested Food

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

What are the reasons my dog vomits undigested food?

What are the reasons my dog vomits undigested food?

Why Is My Dog Throwing Up Undigested Food?

The topic of dogs vomiting undigested food is quite an unglamorous one, but if you own a chowhound who exuberantly gulps down his dinner only to leave you an unpleasant surprise later on, you may be wondering what's going on.

We all know that when food goes down the stomach tube and reaches the stomach, it's supposed to be churned and digested. Afterward, whatever is left should be then sent to the intestinal tract for nutrient absorption to take place.

Therefore things don't add up if we find piles of undigested food that look quite similar to how the food was in its original form, minus the extra sliminess.

Turns out, there can be a few reasons behind your dog vomiting undigested food, but in order to better understand the mechanics behind it, it helps to firstly take a peek into how a dog's digestive system works and what may lead to that unhappy post-mealtime surprise.

Your Doggie's Digestive System

Like most mammals (including humans) dogs chew foods in their mouths, using their teeth to grind up whatever they might be eating. There are also enzymes in their saliva that help break down food into smaller components.

Next, the food passes into the esophagus and then through the cardiac sphincter, also known as the lower esophageal sphincter, or gastroesophageal sphincter, which leads into the stomach.

From there, food gets sloshed around with some pretty heavy-duty acid and then makes its way through to the intestines where the rest of the nutrients are pulled out and distributed to the rest of the body.

Whatever is left over will eventually make its way out of your pooch and end up in a poop bag (hopefully!).

Of course, this is the ideal scenario, one that we see in normal, healthy dogs who are digesting well and all the mechanics are working properly. Problems start when something isn't working as it should.

In general, the average amount of time it takes for the dog's stomach to empty is approximately 2 to 3 hours. It should never take more than 4 to 5 hours.

If undigested food is being therefore thrown up 6 to 8 hours after eating, then Houston we have a problem—there may likely be a problem with the stomach not emptying normally.

If undigested food is being thrown up instead shortly after eating, we may instead have a problem with the dog's esophagus not working properly. However, don't base the reason for your dog's throwing up on the timing of it. Not all are always clear-cut as one would hope for. Consult with your vet to know what may be truly going on.

But now let's take a closer look at some correct definitions and terminology.

Dog Vomiting Versus Regurgitation

You may think that your pup throwing up food is all the same, but there is a difference based on how your dog brings back up the food and the appearance of the expulsed material.

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For example, generally, if your dog wolfs down a meal and shortly thereafter, starts bringing up undigested food with little effort, that’s called regurgitation, (not to be confused with vomiting).

Here's the thing: When dogs regurgitate, it's a rather passive action. The dog simply lowers his head and the undigested material comes out with little to no warning. You may sometimes not be even aware of the fact your dog was sick other than finding a messy pile on the floor. Often though, no messes may be found-and here's a head's up for something gross following in the next paragraph.

Basically, because recently regurgitated food undergoes little changes, many dogs find the undigested food appetizing and will readily eat it since it tastes fresh, with the plus of being warm!

However, not all dogs are chowhounds, so if your dog happens to regurgitate shortly after eating, leaving the mess for you to clean, then expect to find regurgitated content consisting of tube-shaped, undigested food.

A different story is dogs who eat their food, wander off for some time, and then you hear them retching, see abdominal contractions, and shortly thereafter find a mess that includes undigested food, that’s likely vomiting.

Vomiting therefore generally occurs some time after eating, and based on how long it has been since the dog ate, the vomited content can be undigested, partially digested or digested food.

Vomiting, unlike regurgitation, is an active process that is usually preceded by your dog eating grass frantically, licking his lips, drooling, pacing, and then hacking or emitting some other unpleasant sounds, suggesting that your dog is not feeling his best.

Because this food has spent more time in the stomach and has undergone changes, it likely tastes sourer and many dogs will find it far from being tasty-although there are exceptions to the rule.

Now, once again, not everything is clear-cut, so don't base the timing of your dog's throwing up to find out whether your dog is vomiting or regurgitating. According to board-certified veterinarian Dr. Todd R. Tams, regurgitation may take place immediately after ingesting food or fluids, but it can also be delayed for several hours or more.

Whether your dog regurgitates or vomits undigested food, you want to therefore keep an eye on him, especially if it is a sudden onset of continuous throwing up or a recurring problem.

You certainly don’t want your dog to suffer in discomfort any longer than necessary (and hey, if that means you don’t have to clean up their mess, even better!)

Grass eating in a frantic way is often seen in dogs prior to vomiting.

Grass eating in a frantic way is often seen in dogs prior to vomiting.

10 Possible Causes of Dogs Vomiting Undigested Food

Now that we talked about how a dog's digestive system should ideally work and the difference between vomiting and regurgitation, we can take a look at several potential causes for dogs throwing up undigested food. The following are some causes of dogs bringing up undigested food. Of course, there may be several other causes not mentioned here.

1) Simple Digestive Upset

If the vomiting of digested food is just a one-time ordeal, there may be chances the food didn't just agree with the dog. This can happen with dietary indiscretions which make the dog's stomach go topsy-turvy such as when feeding too much table food, giving too many treats, or dogs ingesting something they find outdoors. It can also happen when dogs are abruptly switched over to a new food. In general, for these cases, these issues tend to usually resolve within 24 to 48 hours.

2) A Matter of Dietary Sensitivity

Sometimes, if you start a dog on a new food or supplement that the dog may be sensitive to, this may cause changes to the dog's gastrointestinal motility, causing him to start vomiting several hours later.

What often happens is that the dog's immune system reacts to foreign proteins (which can be found in any sort of food) and once in the gut, their body responds with vomiting and/or diarrhea.

3) Acid Reflux

Some dogs tend to get reflux by throwing up bile and partially digested food at night. Yellow bile in the vomit often signifies that the dog's small intestine is refluxing bile into the stomach causing vomit of yellow color.

This is often a sign of reverse motility, and vomiting food several hours after eating can often be seen at night when dogs lay down making digestion harder and easier for a dog's stomach contents to reflux back up causing irritation of the esophagus and predisposing to vomiting.

4) Inflammatory Bowel Disease

Sometimes, the underlying cause of vomiting undigested food may be inflammatory bowel disease. In dogs, IBD may cause vomiting, and not necessarily the typical diarrhea signs seen in people with IBS. Therefore, you may see vomiting or diarrhea, or even both, depending on what parts of the GI system are affected.

5) A Case of Megaesophagus

A concern with dogs who frequently regurgitate undigested food is some problem with the esophagus, basically, the tube that connects the pharynx to the stomach.

Megaesophagus, in particular, is a condition impacting the esophagus which becomes dilated and has weak muscles. Food or liquids may therefore just sit in it and may be passively regurgitated back up, sometimes several hours after eating.

Megaesophagus may occur as a result of wear and tear after years of excessive pulling on the collar, but may also occur secondary to other disorders such as nerve damage from a foreign body in the esophagus, a low functioning adrenal gland (Addison's disease), hypothyroidism or a condition known as Dysautonomia.

In some cases, it may also arise as a result of a mass in the chest compressing the nerves meant to control the dog's esophageal function.

6) Issue With the Esophagus/Larynx

On top of the megaesophagus, the esophagus may be host to several other problems too. Esophageal and cricopharyngeal achalasia, both swallowing defects and myasthenia gravis, a neuromuscular disease, may cause issues in the esophagus leading to regurgitation of undigested foods.

Lately, geriatric onset, laryngeal paralysis polyneuropathy (GOLPP) has been known to cause a vast array of symptoms in elderly dogs including noisy breathing from the throat, trouble breathing, especially in hot or humid weather, or when the dog is excited or stressed, hoarse barking, hacking, or coughing, gagging with or without regurgitation, hind-end weakness and reduced muscle mass.

7) A Matter of Pancreatitis

Pancreatitis is the inflammation of the dog's pancreas and is often triggered by the dog eating a high-fat meal. In the "acute form," pancreatitis causes dogs to become very sick, developing loss of appetite, severe vomiting, a painful belly and fever.

However, there is also a low-grade, chronic form of pancreatitis which is sort of the "slow burn" version of the acute form. Affected dogs still have an inflamed pancreas but tend to develop periods of pain and nausea with intermittent vomiting.

8) Possible Blockage

In the case of vomiting undigested or partially digested food long after your pup has eaten and therefore has been hanging around a while, there is likely an issue in the connection between your dog’s stomach and the intestines.

A gastric outflow obstruction is a blockage at the level of the pylorus, which is the outlet of the stomach. Such blockage may be interfering with her stomach's ability to empty.

For sake of an example, imagine a foreign object covering the drain of a sink allowing nothing to move out. If the object though bobbed away, then the drain would work normally.

Therefore, in this case, there are chances that food can’t escape the stomach as it should and gets pushed back up and out the other end resulting in vomiting.

9) Gastric Hypomotility

When there is vomiting of undigested or partially digested food occurring 7 to10 hours after ingestion, it would also be important to rule out gastric hypomotility. This may be more likely to occur in an older dog than a younger one.

This really isn't a diagnosis on its own, but is rather a sign of either primary gastric (stomach) disorders or disorders outside the gastrointestinal tract but still capable of affecting it.

10) A Matter of Stress

Stress, excitement or a nervous stomach can cause many symptoms in dogs and vomiting undigested food can sometimes be one of them. Many dogs may lead stressful lives either due to changes in their lives, exposure to frightening noises, or fear of being left alone.

These are just a few of the possible causes of dogs vomiting undigested food. There can of course be several more. Only your vet can accurately diagnose your dog, so please have your dog see one sooner than later.

If your dog vomits partially digested food, see your vet

If your dog vomits partially digested food, see your vet

What Happens at the Vet

It goes without saying that dogs who vomit undigested foods should see the vet so as to address the underlying problem. When you see your vet, make sure to describe carefully what happens, as this will help them differentiate a case of vomiting from a case of regurgitation.

Although you are sure your dog is regurgitating, still describe what you are seeing as sometimes even vets can have a hard time distinguishing the two. If you can, show a video of the episode. A video is worth 1,000 words. No worries, vets are used to seeing gross things!

Once you’re on your way to the vet, you may be wondering what they can do to check what might be causing your pup to vomit or regurgitate undigested food. There are several diagnostic tests your vet may rely on (on top of your detailed descriptions) in order to pinpoint the problem.

Physical Exam

Your vet will often start with a physical examination to feel your dog's stomach and intestines through the abdominal wall (unless your pup is obese in which case this may be a little more difficult). Your vet may be able to even feel if there are foreign bodies in the stomach or intestines causing issues.

Blood Tests

Your vet will likely start with some blood tests such as a complete blood count biochemistry profile (to rule out metabolic disease since vomiting can be a clinical sign of many different disease processes) and thyroid profile to confirm or exclude several conditions. Urine tests and fecal tests may be ordered too.


Your vet may order x-rays to get a better look at the structures in your pup’s body. X-rays can be very helpful in determining whether there may be some foreign object the dog may have ingested and is stuck somewhere or the presence of a mass (tumor/cancer).

The Barium Swallow Test

If your vet suspects an esophageal problem such as megaesophagus or some upper blockage, he or she may require a test called a barium swallow test to see how well your dog's esophagus works and whether the barium is able to make it through the digestive system normally.

The barium is given orally and then a series of x-rays will reveal how this liquid passes through your dog's esophagus, stomach and intestines.


Your vet may also use an ultrasound to get a clearer picture or even do an endoscopy (described below) to see what’s going on.

GI Testing Panels

These are specialized blood tests to confirm or rule out a variety of GI problems. Tests may include a specific test for pancreatitis called a can specPL.


This procedure requires anesthesia. It consists of a video scope being placed through the food pipe and then down into the stomach to look at the stomach and possibly take small biopsies.

Referral to a Specialist

Sometimes, persistent vomiting in dogs may not be easy to diagnose. If you have been to the vet several times without resolving the issue or your vet feels like your dog's case is a tough nut to crack, a referral to a board-certified specialist can turn insightful.

Remedies for Dogs Vomiting Undigested Food

Treating vomiting or regurgitation in dogs can range from diet changes to the simple withholding of food for a brief window of time and slowly introducing it back with easy-to-digest food like cottage cheese and boiled rice, to intravenous IVs for fluids and surgery on the most extreme spectrum. Your vet will be able to advise on the best way to treat your pup’s condition.

It goes without saying therefore that treatments will vary depending on the underlying cause.

For instance, for minor cases of digestive upset due to a recent diet change, vet-approved dog upset stomach remedies may be all that is needed to calm things down. Check with your vet if this may be the case.

Cases of food sensitivities may benefit from dietary changes where dogs are fed a novel protein or some other type of 'sensitive stomach diet.

Motility disorders may benefit from a prescription of metoclopramide (Reglan) as well as feeding less more frequently and in smaller amounts.

In the case of an obstruction, surgery is often needed to remove the foreign object.

My beloved Rottweiler has seen the vet for vomiting undigested food.

My beloved Rottweiler has seen the vet for vomiting undigested food.

My Rottweiler's Experience

Around November 2018, my male Rottweiler dog was burping a lot during the day, and at night/wee hours of the morning, I would wake up to him vomiting his partially digested food about 7-8 hours after his dinner. I, therefore, saw my vet for the intermittent vomiting of undigested food and bile at night, and after a physical examination, my vet prescribed Pepcid, but it didn't seem to help much.

On the next visit, she referred us to a very knowledgeable board-certified veterinarian specializing in internal medicine. She did an ultrasound which yielded a diagnosis of mild pancreatitis, although the Idexx radiologist did not read it the same way, she suggested diet adjustments to a lower fat food just in case.

On top of dietary changes, this specialist was aware of recent studies proving that Prilosec (omeprazole) was more effective than Pepcid so she decided to prescribe that along with metoclopramide (Reglan), a medication known for hastening gastric emptying and intestinal transit.

After this, I noticed that the nights I gave the Reglan to him (along with his Prilosec), he slept like a baby (no lip-smacking, burping, vomiting of bile or undigested food).

I was told that Reglan had sphincter-tightening properties at the level of the junction of the esophagus and stomach and that perhaps Kaiser had some motility disorder.


  • VetFolio: Is it Vomiting or Regurgitation by Davic. C. Twedt. DVM DACVIM
  • Handbook of Veterinary Internal Medicine. Dr. Hamed Attia Mohamed
  • Textbook of Veterinary Internal Medicine, Expert Consult, 8th Edition.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2020 Adrienne Farricelli


Adrienne Farricelli (author) on October 23, 2020:

I agree Pamela, there are so many health conditions dogs and humans share. I think one that dogs will never get though is appendicitis, as dogs unlike us don't have an appendix. Now that I think about it, it could likely be my dog was in some pain/discomfort when he was diagnosed with mild pancreatitis as he would get up from resting, drool and start smacking his lips. Fortunately, the internist got to the bottom of it.

Adrienne Farricelli (author) on October 23, 2020:

Devika, it is so true that vomiting in dogs (and in humans too!) is a self-defense mechanism and so important to keep us safe from harmful substances. Too bad that at times it gets out of hand, but that's the dashboard warning light that we need to dig deeper and find how to to help our furry friends.

Linda Crampton from British Columbia, Canada on October 23, 2020:

This is a very informative and useful article. I've had to deal with vomiting in my dogs over the years, and one of my dogs had pancreatitis. Your article is important. Thank you for creating it.

Pamela Oglesby from Sunny Florida on October 23, 2020:

Even though I do not have a dog right now I find your articles so interesting. It sounds like the physical problems a dog has are very similar to that of a human being.

I wonder if your dog was having pain due to the pancreas problem I have always been told that pancreatitis isery painful in humans and I would think any problem with the pancreas would be painful for a dog also. This is a very detailed, excellent article, Adrienna.

Heidi Thorne from Chicago Area on October 23, 2020:

Like yours, our golden was diagnosed a few weeks ago with pancreatitis, confirmed with blood tests and other diagnostics. He is a chow hound. So it was difficult to figure what was going on with him at first. He had a very bad day with multiple episodes on both ends. Luckily, the vet said he won't need any meds unless the episodes become more frequent or worse. For now it's just monitoring his diet and symptoms.

And, yes, we've experienced the "hey, there's some tasty undigested bits in there" situation. Good God!

Anyway, thanks for sharing this valuable information!

Devika Primić from Dubrovnik, Croatia on October 23, 2020:

Adrienne Farricelli, dogs are amazing pets. To vomit undigested food is a way to make them feel better. Interesting and I like your hubs about dogs. Their characteristics, and so much more you ahve shared here.

Peggy Woods from Houston, Texas on October 23, 2020:

You cover so many different topics with regard to what can happen to our pets. It is very informative and appreciated. Over the years, a few times our dogs would eat some grass and then vomit. But it never happened frequently or was persistent. Thanks for writing article like this.

Sp Greaney from Ireland on October 23, 2020:

It is one of those things you hope is caused by the food. It's awful seeing any pet vomiting for any reason. You feel so helpless. I would never have expected so many causes of this condition in dogs.

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