Dog Throwing Up Mucus? What Each Color Means & When to Worry

Key takeaways

• Slimy, stringy or jelly-like vomit is mostly mucus, the stomach's protective coating, brought up from an empty or irritated stomach, often first thing in the morning.
• Yellow slime is bile mixed with mucus; brown, coffee-ground material is digested blood and needs a vet, per Cornell's vets.
• White froth or "phlegm" after a honking cough is often kennel cough, a respiratory problem rather than a stomach one.
• In a study of dogs with bilious vomiting syndrome, 12 of 17 improved with treatment that included more frequent meals and a late-evening feeding.
• Retching that brings up nothing or only foam, with a swelling belly, can be bloat: go to an emergency vet now.

A dog vomiting mucus is usually bringing up slime from an empty, irritated stomach: the stomach's protective mucus mixed with saliva and gastric secretions, often before breakfast. In a bright dog, the odd episode is minor. Two questions matter: is it really vomiting (slime after a honking cough is often kennel cough), and are there red flags such as blood?

Quick answer: For one or two mucus vomits in a bright dog, rest the stomach, offer sips of water and bland food, and watch for 24 hours; call your vet if it repeats or the mucus is bloody or brown.

What does it mean when a dog vomits mucus or phlegm?

Mucus is the slippery coating that protects the stomach and esophagus. On an empty stomach, it's all that's left to come up, so the vomit looks stringy, slimy or like clear jelly. Whipped with air, the same slime becomes the white foam dogs throw up. "Phlegm" can also be airway mucus from a cough, so notice what happened just before.

Dog vomit with mucus: what the color and texture mean

The Merck Veterinary Manual notes that vomit from sudden gastritis may contain bile, froth, fresh blood or coffee-ground digested blood. Plain fluid without slime is covered in our guide to a dog throwing up water or clear liquid.

What causes a dog to throw up mucus?

Empty-stomach irritation. The usual pattern. Food takes hours to digest, and long gaps between meals let acid irritate the stomach, so slime comes up, often early in the morning. Yellow means bile; see throwing up yellow bile.

Dietary indiscretion. Grass and rich scraps trigger vomiting that usually settles within a day (see our upset stomach guide); our list of human foods dogs can eat shows safe leftovers.

Kennel cough that looks like vomiting. Merck's kennel cough chapter describes a "goose honk" cough that may be followed by retching and gagging. Recent boarding or daycare raises the odds; our guide to why dogs cough covers other causes.

Regurgitation. Slime-coated material that slides out with no heaving points to the esophagus. Cornell's Riney Canine Health Center notes that regurgitation doesn't include retching and may indicate an esophageal problem. See dog food for acid reflux if reflux is the suspect.

Underlying conditions. Infections, pancreatitis, an intestinal blockage or chronic GI disease can all cause repeated mucus vomiting. Cornell says vomiting even once a week may indicate a disease; our guide on why dogs keep throwing up explains the workup.

How to settle a dog throwing up mucus at home

• Rest the stomach. Cornell suggests withholding food, but not water, for about 12 hours; offer small, frequent sips.
• Feed bland food. Plain white rice and boiled chicken for two days, per Cornell; see our bland diet for dogs guide.
• Close the overnight gap. If mornings are the pattern, split food into 2 or 3 meals plus a small bedtime portion.
• Keep the diet consistent. Abrupt changes and rich extras keep a touchy stomach touchy; see food for sensitive stomachs.

12 of 17 dogs with bilious vomiting syndrome (early-morning vomiting of bile) improved with treatment that included frequent feedings and late-evening meals plus medication, in a Colorado State University study of cases from 2002 to 2012. - Journal of the American Animal Hospital Association, 2016

Red flags: when mucus vomit needs a vet today

• Retching that brings up nothing or only foam, a swelling belly and drooling, which the American College of Veterinary Surgeons lists among early signs of bloat in dogs; go now
• Repeated vomiting, or a dog who can't keep water down
• Blood in the vomit, or material that looks like coffee grounds
• Gagging with labored breathing, or pale or blue-tinged gums
• A swallowed object or toxin; call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435
• Puppies and seniors vomiting repeatedly, since they dehydrate faster

What most guides on dog mucus vomit don't tell you

The "vomit" may be a cough. The American Veterinary Medical Association says kennel cough can "involve froth that looks like vomit." Listen for the honk before the foam, and call the clinic before you go in, as the AVMA advises.

A morning-vomiting label can hide something else. In the Colorado State study, the diagnosis was later changed in 3 dogs (to stomach cancer, dietary indiscretion and liver disease), and few dogs had a full workup. Our take: try a bedtime snack first, but if morning mucus vomiting hasn't stopped within a couple of weeks, ask your vet to dig further.

Frequently asked questions

Why is my dog throwing up clear, jelly-like mucus?

Clear, jelly-like vomit is usually stomach mucus and saliva from an empty or irritated stomach, often after grass or a long gap between meals. If it slides out with no heaving, it's more likely regurgitation from the esophagus, which needs a vet. Repeated episodes, or any blood, mean calling your vet.

Why does my dog vomit mucus in the morning?

Overnight is the longest stretch your dog's stomach sits empty, so acid and bile irritate the lining before breakfast. A small bedtime meal helps many dogs; if it continues past a couple of weeks, see your vet.

Why is my dog throwing up yellow mucus?

Yellow mucus is bile mixed with stomach mucus, usually on an empty stomach. One episode is common. Frequent yellow vomiting, or vomiting with appetite loss or lasting more than 24 hours, needs a vet check.

Is mucus vomit different from mucus in stool?

Yes. Both come from an irritated GI lining, but slime in stool points to the colon; see mucus in dog poop. A dog with both vomiting and slimy diarrhea loses fluid fast and should see a vet sooner.

When should I worry about my dog vomiting mucus?

When it happens more than twice in a day, contains blood or coffee-ground material, or comes with lethargy, a swollen belly, fever, a honking cough or a dog who can't keep water down. Any of those means calling the vet today.

The bottom line: A dog vomiting mucus usually has an empty, irritated stomach with a feeding-schedule fix, but know the impostor (kennel cough) and the emergency (bloat) by sight. Spot & Tango's recipes are formulated with pet nutritionists to meet AAFCO standards and pre-portioned, which makes a 3-meal day easy. Take the recipe quiz to build your dog's plan.

Questions about feeding schedules? Our customer care team is happy to help.

About this article

Written by the Spot & Tango editorial team, which covers canine nutrition and health for dog owners. Reviewed by a licensed veterinarian; facts and figures checked.

References & Sources:

• Cornell University College of Veterinary Medicine, Riney Canine Health Center, Vomiting. https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-topics/vomiting
• Merck Veterinary Manual, Disorders of the Stomach and Intestines in Dogs (dog owners edition). https://www.merckvetmanual.com/dog-owners/digestive-disorders-of-dogs/disorders-of-the-stomach-and-intestines-in-dogs
• Merck Veterinary Manual, Kennel Cough. https://www.merckvetmanual.com/respiratory-system/respiratory-diseases-of-small-animals/kennel-cough
• American Veterinary Medical Association, Canine infectious respiratory disease complex (kennel cough). https://www.avma.org/resources-tools/pet-owners/petcare/canine-infectious-respiratory-disease-complex-kennel-cough
• Ferguson L., Wennogle S.A., Webb C.B., Bilious vomiting syndrome in dogs: retrospective study of 20 cases (2002-2012), Journal of the American Animal Hospital Association (2016). https://doi.org/10.5326/JAAHA-MS-6300
• American College of Veterinary Surgeons, Gastric Dilatation-Volvulus. https://www.acvs.org/small-animal/gastric-dilatation-volvulus/
• ASPCA Animal Poison Control Center, (888) 426-4435. https://www.aspca.org/pet-care/aspca-poison-control