What Is Bilious Vomiting Syndrome in Dogs?

There are few sounds as jarring as waking up in the middle of the night to the sound of your dog heaving. Your first instinct is to rush to their side, flipping on the light to check if they are okay and clean up the puddle of yellow or greenish liquid.

This specific type of vomit, a clear sign of bilious vomiting syndrome (BVS), is a surprisingly common occurrence for many dog parents. While seeing your dog feeling ill is never easy, understanding what’s happening and how to help is key to making them more comfortable.

In this blog post, I’ll explain what BVS is, why it might be happening to your dog, practical ways to manage and prevent it to help your dog feel their best, and when you should contact your veterinarian. 

What is Bilious Vomiting Syndrome?

To truly understand what’s happening, you need to first understand the role of bile in your dog’s system. What exactly is it? Think of bile as a natural digestive detergent. Produced by the liver and stored in the gallbladder, this yellowish-green fluid plays a key role in breaking down fats during the digestion process. It’s normally released into the small intestine to help with this process after your dog eats.

So, why would your dog be throwing up this important fluid? Bilious vomiting syndrome occurs when your dog’s stomach is empty for a prolonged period, usually after a long stretch between meals, such as overnight. This causes the normal contractions of the stomach to slow down or even stop. Bile from the intestine can reflux, or flow backward, into the empty stomach at this stage.

The presence of bile, along with stomach acid, can irritate the sensitive lining of the stomach. It is this irritation that triggers the feelings of nausea, ultimately leading to vomiting. The tell-tale yellow or yellowish-green appearance of the vomit is simply the bile itself, and because there’s no food in the stomach, it comes up as a liquid. This is the key sign that you’re dealing with bilious vomiting and not your dog throwing up an undigested meal.

Why, Exactly, Does Bilious Vomiting Syndrome Happen?

The most common trigger is simply a long gap between meals. Many dogs, especially those fed only once or twice a day, go 10 to 12 hours or more between their evening meal and their morning one. This long period of fasting allows bile to accumulate and irritate the stomach lining, which is why BVS is most often experienced first thing in the morning.

However, an empty stomach isn’t the only factor at play. Other issues can contribute to or worsen BVS. For instance, irregular feeding schedules can disrupt your dog’s digestive rhythm, making them more susceptible to reflux. A dog whose system is used to eating once a day is less likely to have a problem with this time between meals than a dog who is normally fed three times a day and misses a meal or two.

While not a direct cause, eating something they shouldn’t (like garbage) can also throw their digestive system into a state of upset, leading to a period of nausea and subsequent vomiting.

More complex digestive issues may also be responsible for your dog’s struggles. If your dog is experiencing issues with gut movement, like slow or abnormal digestive patterns, it can cause a backup of fluids and lead to BVS. Gastroesophageal reflux disease (GERD), also known as acid reflux, can cause a similar type of stomach irritation.

It’s also important to be aware that BVS may be a symptom of a more serious underlying medical condition. Pancreatitis, inflammatory bowel disease (IBD), or even a gastrointestinal obstruction can all cause episodes of vomiting. Because of this, what may seem like a simple case of BVS may actually be a sign of a more serious, developing problem. This is why paying close attention to the frequency and other symptoms is so important.

When to Contact Your Veterinarian

Knowing when to be concerned is an important, but sometimes challenging, part of being a dog parent. The occasional, one-off episode of bilious vomiting in an otherwise happy and healthy dog may not be an immediate cause for alarm, especially if it happens after a long period of fasting. However, if vomiting becomes a regular occurrence or is accompanied by other signs of trouble, it’s a clear signal that a vet visit is warranted.

Here are some red flags that indicate it’s time to see a vet:

• Frequency: Your dog is vomiting bile multiple times a day for more than 24 hours.
• Accompanying Symptoms: The vomiting is accompanied by other signs of illness, such as lethargy, a significant loss of appetite, diarrhea, or signs of abdominal pain.
• Changes in Vomit: The vomit contains blood, which can appear as bright red streaks or have a dark, coffee-ground-like appearance.
• Signs of Dehydration: Your dog shows signs of dehydration, such as sunken eyes, lethargy, or loss of skin elasticity (the skin stays “tented” when you gently pinch and release it).
• Unproductive Retching: Your dog is repeatedly trying to vomit, but nothing is coming up. This could be a sign of a potential obstruction or a serious condition like gastric dilation-volvulus (GDV), also known as bloat, which is a life-threatening emergency.

Your vet can perform a thorough physical exam and, if necessary, run diagnostic tests such as blood work, fecal analysis, or abdominal X-rays to rule out other potential medical conditions. A proper diagnosis is essential because if a more serious underlying issue is present, addressing it is the only way to truly resolve the symptoms of BVS.

Tips for Managing and Addressing Bilious Vomiting Syndrome

Once you’ve ruled out more serious conditions with your vet, the good news is that BVS is often very manageable. The main goal in managing and preventing BVS is simple: avoid letting your dog’s stomach sit completely empty for too long at any given time.  

Your Dog’s Feeding Schedule

For most dogs, the simplest solution is to adjust their feeding schedule. Instead of feeding one or two large meals a day, which creates long stretches of time with an empty stomach, consider breaking your dog’s daily food allowance into three or four smaller portions. This approach, often referred to as “grazing,” helps ensure that there is always food in their digestive system. A stomach with a little bit of food in it is far less likely to be irritated by bile and acid.

An effective solution for dogs who struggle with BVS in the early morning, like we originally were with my dog Lucier, is to provide a small bedtime snack. Morning vomiting occurs because the stomach has been empty all night. By giving them a small, easily digestible snack right before bed, you ensure there is something to absorb stomach acid and bile overnight. This could be a small handful of kibble, a dental chew, or a single biscuit.

If your dog’s morning vomiting is particularly bad or isn’t prevented by a bedtime snack, you may even consider a very small middle-of-the-night feeding. Setting a phone alarm for a quick 2-minute trip to the kitchen can make a significant difference for some dogs. You can even pre-portion the food into a sealed container to make those nighttime feedings easy, even when you’re feeling half-asleep.

Reconsider What You’re Feeding Your Dog

In some cases, the type of food can also be a factor. If your dog has a sensitive stomach, your vet may recommend switching them to a highly digestible commercial diet. These diets are typically formulated with ingredients that are easy on their digestive tract and often lower in fat and fiber, which can help ensure that food passes through the stomach at a normal, healthy rate (not too quickly, leaving their stomach empty).

Foods high in fat can also help to slow down gastric emptying, meaning food sits in the stomach for longer. For some dogs, reducing the fat content in their diet can help prevent the backup of stomach contents and fluids that can contribute to BVS.

If you are considering making a significant change to your dog’s diet, start with a call to your veterinarian. They can help you determine the proper diet for your pup’s unique needs and how to best introduce it to avoid making them feel sick.

Try Incorporating New Ways of Feeding

In addition to reconsidering what you’re feeding, you may need to reconsider how you’re feeding your dog. If your dog eats too quickly, gulping down their food, it can lead to trouble. Try incorporating new ways to feed your dog and slow them down, such as puzzle feeders, slow feeder dishes, interactive treat toys, or snuffle mats.

If budget is a concern, there are also simple DIY solutions you can try. Consider sprinkling your dog’s food across the floor, in the grass outside (commonly referred to as “nature’s snuffle mat”), or create a DIY busy box using boxes, egg cartons, and newspaper from your recycling bin.

By slowing down consumption and encouraging more thorough chewing of their food, you can help to improve their overall digestion and reduce the risk of stomach troubles. Not only do these products encourage them to eat at a healthier pace, but they also turn mealtime into a game, providing much-needed mental enrichment.

Medical Interventions (When Recommended by Your Vet)

If dietary and scheduling changes aren’t enough to manage your dog’s BVS, or if their condition is severe, your vet may suggest medication.

Some medications, known as pro-motility drugs, can help regulate the movement of the stomach and intestines. This helps ensure that food and bile move forward through the digestive tract in the right direction, preventing reflux and the problems it triggers. In cases where excess stomach acid is a major contributing factor to the stomach irritation, your vet may prescribe an acid-reducing medication. These drugs decrease the amount of acid produced in the stomach, thereby reducing irritation.

Please note that these are not over-the-counter solutions. All medical interventions should be discussed with and prescribed by your vet to ensure they are safe and appropriate for your dog’s specific needs. Do not introduce any medications unless they are under veterinary supervision.

Simple Steps for Lasting Relief

Waking up to your dog vomiting is never a pleasant experience. However, understanding what causes bilious vomiting syndrome is the first step toward finding a solution. While it can sometimes be a sign of a more serious underlying issue, in most cases, it’s a manageable condition that can be resolved with simple adjustments to your dog’s routine.

By focusing on preventing an empty stomach through more frequent feedings, a bedtime snack, and working with your vet to address any challenges along the way, you can significantly reduce or even eliminate episodes of morning vomiting altogether.

Your dedication to your dog’s health and happiness is what matters more. With a little proactive management, you can help your best friend feel comfortable and ready to take on the day ahead.

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