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 VeterinarianKnowing 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.
