Why Is My Dog Vomiting Yellow? Reasons & What to Do (Vet Answer)

Unfortunately, vomiting can be a common part of having a dog, and their vomit can come in many forms and be a variety of colors. If your dog is vomiting yellow, it’s most likely bile, which could be tied to several different causes, including fasting, pancreatitis, and allergies. If the vomiting is severe or accompanied by other signs, see your veterinarian as soon as possible. Otherwise, you may be able to track down the cause yourself. We can help with that by going over the most common reasons that a dog would vomit yellow and what you can do to help.

Why Is My Dog’s Vomit Yellow?

The most common reason a dog’s vomit is yellow is that it contains bile. Bile is a digestive product produced by the liver and stored in the gallbladder and is made mostly of water, cholesterol, bile acids, and bilirubin, which gives it its yellow color. It’s normally released when your pup eats food in preparation for digestion. However, in some cases, it may leak into the small intestine and back up into the stomach without the presence of food.

Bile’s main function is to break down fats. It’s also alkaline as opposed to acidic, like the stomach acid. You may remember from chemistry class that acids and alkaline bases neutralize each other, which helps protect the lining of the small intestine from the harshness of the stomach acid. When bile leaks into an empty stomach, that acid-base reaction can create an upset tummy.

Another reason your pup may be throwing up yellow stuff is that they ate something yellow. This could happen if they got into your art supplies or if their dog food or treats are dyed unnaturally yellow.

What Causes a Dog to Vomit Yellow?

Bile is the most likely reason that your dog’s vomit is yellow, but why are they vomiting that bile? There could be several reasons behind that.

1. Too Much Time Between Meals

Some dogs may vomit bile if they haven’t eaten for a long time. You’ll typically see this first thing in the morning after your dog has fasted all night. This is typically called bilious vomiting syndrome, and it’s suspected that during the fasting period, bile backs up into the stomach, creating that acid-base reaction. Dogs may appear nauseated before they vomit, such as lip smacking, drooling, and panting.

Bilious vomiting syndrome is more of an annoyance than it is a threat, but any recurrent vomiting should be checked out by a vet. If other causes are ruled out, your vet may advise you to feed your dog larger meals at night or give them a small snack right before bed to help tide them over and keep the bile where it should be.

2. Inflammation of the Digestive System

Vomiting yellow stuff is usually related to an empty stomach, since food helps neutralize bile and prevent it from aggravating the stomach and leading to vomiting. As you can imagine, anything that decreases your dog’s appetite or aggravates their stomach can cause vomiting of yellow bile. That could be an infection, parasites, eating something that they shouldn’t have, ulcers, or even cancer.

Besides vomiting yellow, dogs will have a decreased appetite, possibly diarrhea, lethargy, and stomach pain. See your veterinarian if your dog vomits, yellow or otherwise, more than a couple of times in a 24-hour period or if they are showing other signs of issues.

3. Intestinal Blockage

Some dogs don’t discriminate at all about what goes into their mouths, and that can sometimes get them into trouble. When a dog eats something that isn’t digestible and if it is large enough, it can get stuck in the intestines, backing up traffic behind it. This may cause a dog to vomit, since the ingesta has no place else to go. Once a dog vomits their stomach empty, they can start to vomit bile.

Intestinal blockages can be quite painful, and you may see diarrhea or a lack of any fecal material altogether. Blockages are an emergency, so see your vet as soon as possible. Some may require surgery to be removed.

4. Pancreatitis

The pancreas is an organ that’s involved in digestion and other tasks. It can become inflamed after a high-fat meal or for reasons unknown. This inflammation can cause vomiting, diarrhea, and stomach pain. If a dog’s stomach is empty, that vomit could contain a large amount of bile, turning it yellow.

Pancreatitis can quickly become severe, so you should see your vet as soon as possible to get it under control.

5. Food Allergies

Similar to things that inflame the digestive tract, food allergies can cause a pup to vomit yellow. These can be difficult to figure out because they can show up suddenly after your dog ingests a food that they’ve happily eaten for many years. Allergies may also cause itchy, red skin or chronic ear infections, so be sure to contact your vet if you suspect that your dog may have developed a food allergy. They can walk you through how to do an elimination trial or how to switch to a novel protein diet.

Should I Be Worried If My Dog Throws Up Yellow?

Most causes of yellow vomit don’t warrant a midnight veterinary run, but you should see a vet if the vomiting is more than a one-time thing. This is especially true if your pup is displaying any other signs.

If you are concerned about the well-being of your pet or if they're displaying any of the symptoms above, you should contact your vet.

Is There a Home Remedy for Bile Vomiting in Dogs?

If this is the first time that you’ve seen your dog vomit yellow and they’re feeling better already, you may feel free to sit back and simply monitor the situation. Consider contacting your vet just so they’re in the loop should things progress.

With any luck, your pup ate something that was less than agreeable to their stomach, and they just needed to get rid of it. Keep in mind that vomiting bile usually happens with an empty stomach, so they might have already vomited their food or it’s been a little while since they did eat.

Now, if vomiting yellow is a frequent occurrence, see your vet to rule out other causes, and then try feeding your dog smaller meals more frequently. Focus on giving them a larger meal in the evening or a light snack before bed. If that doesn’t seem to be the problem, consider switching to a novel protein diet.

If your dog is coming off of another illness and is now vomiting bile, you should see your veterinarian to make sure everything is okay, and then start them on a bland diet. This can help settle the digestive system, and offering something other than their regular kibble may entice them to eat if they are feeling less than hungry.

Conclusion

When a dog is vomiting yellow, it usually means there is bile in the mix. Bile normally is released in the small intestines but may reach the stomach when a dog hasn’t eaten in a long time or if other things are causing inflammation or irritation to the digestive tract. If your dog vomits yellow regularly or is showing signs of diarrhea or lethargy, consult your vet as soon as possible.

Featured Image Credit: ThamKC, Shutterstock