Why Is My Dog Sick? Vomiting in Dogs and When to Call the Vet

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Updated September 2026

Dogs can vomit for lots of reasons. Sometimes it is a short-lived stomach upset after eating something unusual, but vomiting can also signal poisoning, a blockage, pancreatitis, infection, heatstroke, or another illness.

If your normally healthy adult dog has been sick once but is bright, comfortable and behaving normally, you may be able to monitor them closely. Repeated vomiting, blood, abdominal pain, marked lethargy, collapse, suspected poisoning, or repeated attempts to vomit without bringing anything up need veterinary advice.

Puppies, older dogs and dogs with existing medical conditions deserve extra caution because they can become unwell or dehydrated more quickly.

For wider advice on recognising an emergency, see my Dog Health & First Aid Guide and When Should I Call the Vet?

Summary

• One episode of vomiting in an otherwise bright, healthy adult dog is not automatically an emergency.
• Repeated or continuous vomiting needs veterinary advice.
• Contact your vet promptly if there is blood in the vomit, abdominal pain, marked lethargy, dehydration, disorientation or collapse.
• Repeated retching with little or nothing coming up, particularly with a swollen abdomen, can be a sign of GDV and is an emergency.
• Yellow or green foamy vomit often contains bile. Its colour alone does not tell you why your dog is vomiting.
• Do not diagnose poisoning from the colour of your dog’s vomit.
• Do not try to make your dog vomit after suspected poisoning unless a veterinary professional specifically tells you to.
• Do not give charcoal tablets, human medicines or kitchen-cupboard remedies without veterinary advice.
• If your dog has vomited once and otherwise seems well, current veterinary guidance supports rest, fresh water, little and often, and small amounts of a suitable bland diet.
• If you are worried about your dog, phone your vet. You do not need to work out the diagnosis first. (PDSA)

Why is my dog being sick?

Vomiting is a symptom rather than a diagnosis.

Dogs can be sick for relatively minor reasons, such as eating something that disagrees with them or changing food too quickly. But vomiting can also occur with illnesses that require veterinary treatment.

Possible causes include:

• scavenging or eating something unusual
• eating too much
• a sudden change in food
• gastroenteritis
• parasites
• travel sickness
• pancreatitis
• swallowing a foreign object
• poisoning
• medication reactions
• liver or kidney disease
• infections
• heatstroke
• GDV, sometimes called bloat or a twisted stomach

You cannot reliably tell which of these is responsible simply by looking at the vomit. What matters is what your dog has brought up, how often it is happening and, most importantly, how your dog is behaving overall.

When should I call the vet because my dog is vomiting?

Contact your veterinary practice if your dog keeps vomiting or if something about their condition worries you.

I would be particularly concerned about:

• repeated or continuous vomiting
• blood in the vomit
• vomiting accompanied by significant diarrhoea
• a painful or swollen abdomen
• marked lethargy or weakness
• refusing food or water
• being unable to keep water down
• sticky gums, sunken eyes or other signs of dehydration
• disorientation
• collapse
• suspected poisoning
• suspected ingestion of an object
• symptoms that are getting worse rather than better

Current PDSA guidance lists continuous vomiting, blood, abdominal pain, lethargy, dehydration, disorientation and collapse among reasons to contact a vet.

If you look at your dog and think, “This isn’t normal for them”, that matters too.

You know your own dog better than an online checklist does.

My dog keeps trying to be sick, but nothing comes up

Repeated attempts to vomit without producing much or anything at all can be an emergency.

Continuous retching, especially when combined with a swollen or bloated abdomen, can signal gastric dilatation-volvulus, usually shortened to GDV. This is a life-threatening condition.

Do not wait to see whether it settles overnight.

Contact an emergency vet immediately.

This is also covered in my When Should I Call the Vet? guide.

What is the difference between vomiting, retching and regurgitation?

These can look similar, but they are not the same thing.

Vomiting

Vomiting normally involves nausea followed by abdominal effort or retching before stomach contents are brought up.

You may also notice signs such as:

• lip licking
• swallowing
• drooling
• restlessness
• reduced appetite

Retching

Retching is the heaving action of trying to vomit.

A single retch may not mean anything serious, but continuous unsuccessful retching deserves urgent attention, particularly if the abdomen is swollen.

Regurgitation

Regurgitation is usually much more passive.

Undigested food or liquid comes back up without the obvious abdominal effort associated with vomiting.

A dog may occasionally regurgitate after eating too quickly, but repeated regurgitation can also occur with medical conditions such as megaoesophagus or gastro-oesophageal reflux. If it keeps happening, speak to your vet rather than assuming your dog is simply eating too quickly

What does the colour of my dog’s vomit mean?

The appearance of vomit can provide useful information for your vet, but you should not use it to diagnose your dog at home.

Yellow or green foamy vomit

Yellow or green fluid can contain bile.

You may see it when there is relatively little food in the vomit, but yellow bile does not prove that your dog is simply hungry or that their stomach is empty.

If it keeps happening, speak to your vet rather than repeatedly changing feeding times yourself.

Food in the vomit

You may see partially digested or undigested food.

Think about:

• what your dog ate
• how recently they ate
• whether they have scavenged
• whether their food has recently changed
• whether vomiting has happened more than once

That information can be useful if you need to speak to your vet.

Blood in vomit

Blood may appear bright red, but partially digested blood can look dark brown, black or similar to coffee grounds.

Contact your vet promptly if you see blood in your dog’s vomit.

Grass

Dogs sometimes vomit grass.

Seeing grass in the vomit doesn’t tell you whether eating grass caused the vomiting or whether the dog ate grass because it was already feeling nauseous.

Look at the whole dog rather than trying to diagnose from one ingredient in the vomit.

Read my guide on Why does my dog eat Grass

Does bright green vomit mean rat poison?

No. You cannot diagnose poisoning from the colour of your dog’s vomit.

The previous version of this guide suggested that bright green vomit indicated rat poison. I have removed that advice.

If you know or suspect that your dog has eaten rat poison, pesticides, medication, chemicals or another potentially toxic substance, act on the exposure itself. Do not wait for the vomit to change colour or for symptoms to appear.

Contact your vet or Animal PoisonLine promptly.

Animal PoisonLine is the UK 24-hour specialist service for pet owners concerned about possible poisoning.

Should I make my dog vomit if they have eaten something poisonous?

No. Do not try to make your dog vomit at home unless a veterinary professional specifically instructs you to do so.

No universally safe home method exists.

Animal PoisonLine warns that attempts to cause vomiting using substances such as salt, hydrogen peroxide or detergent can create additional problems. Some poisons can also cause further injury on the way back up or create a risk of material being inhaled into the lungs.

If you suspect poisoning:

1. Move your dog away from the source if it is safe to do so.
2. Contact your vet or Animal PoisonLine.
3. Keep the packaging, label or product information if available.
4. Try to establish what was eaten, approximately how much and when.
5. Follow the professional advice you are given.

Do not give salt water.

Do not give charcoal tablets from your first-aid cupboard.

Do not try a remedy you found online.

The right response depends on what your dog has been exposed to. (Animal PoisonLine)

My dog has vomited once but seems completely normal. What should I do?

If your normally fit and healthy adult dog has been sick once and is otherwise bright, comfortable and behaving normally, close monitoring may be reasonable.

Current PDSA advice includes:

• allowing your dog to rest
• offering fresh water little and often
• avoiding rich or fatty foods
• offering small portions of a highly digestible, low-fat bland diet where appropriate
• watching closely for further vomiting or other symptoms

If vomiting continues, your dog becomes unwell, or you are concerned, contact your vet.

This is different from the old internet rule of automatically removing all food and water for many hours.

I have removed that advice from this page.

Should I stop my dog drinking after they have been sick?

Do not routinely remove drinking water from a dog simply because they have vomited once.

Dogs lose fluid when they vomit, so hydration matters.

Offer fresh water little and often rather than encouraging a dog to gulp a large amount at once. If your dog repeatedly vomits after drinking or cannot keep water down, contact your vet. (PDSA)

Puppies, elderly dogs and dogs with medical conditions can be particularly vulnerable to dehydration.

What should I feed my dog after vomiting?

If your otherwise healthy adult dog has vomited once, seems well and is keeping water down, small portions of an easily digested, low-fat bland diet may be appropriate.

PDSA gives examples such as plain cooked chicken breast or white fish with rice, while veterinary bland diets are also available. Once vomiting stops, you can gradually reintroduce the normal diet

This is short-term stomach-upset advice, not a nutritionally complete long-term diet.

If your dog has an existing medical condition, is on a prescription diet, is very young or old, or regularly develops digestive problems, ask your vet what is appropriate for that individual dog.

For general feeding advice, see my Dog Food & Nutrition Guide.

If you are changing your dog’s normal diet, read How Do I Change My Dog’s Food?

Can changing dog food make a dog sick?

Yes. A sudden diet change can cause digestive upset in some dogs.

That does not mean every episode of vomiting after changing food is definitely caused by the food.

If your dog is otherwise well and you have a genuine reason to change diets, introduce the new food gradually unless your vet has advised otherwise. If vomiting repeats or is accompanied by diarrhoea, pain, lethargy, loss of appetite, or another worrying symptom, contact your vet.

Should I give ginger, honey, charcoal or another home remedy?

I would not routinely treat vomiting with kitchen-cupboard remedies, supplements or human medicines.

The previous version of this article suggested remedies including ginger and charcoal tablets. I have removed those recommendations.

Vomiting has too many possible causes for me to recommend treating it blindly.

Something that appears to settle a mild stomach upset could also delay veterinary treatment when the real problem is a blockage, poisoning, pancreatitis or another illness.

If your dog needs treatment, let your veterinary team decide what is appropriate.

What information should I give my vet?

You do not need to make a diagnosis before calling.

Useful information can include:

• when the vomiting started
• how many times your dog has vomited
• when they last ate
• what they ate
• whether their normal food has changed
• anything they may have scavenged
• possible access to medicines, chemicals or toxic food
• whether they have diarrhoea
• whether they are eating and drinking
• their normal and current behaviour
• any signs of pain
• medication they currently take
• existing health conditions

A photograph of the vomit can sometimes be useful.

If you can safely identify something obvious in it, such as food, grass or part of an object, tell the vet. You do not need to rummage through potentially contaminated material with your bare hands.

Why are puppies more of a concern when they vomit?

Puppies have less reserve than healthy adult dogs and can become dehydrated more quickly.

Vomiting can also occur with serious infections such as parvovirus.

Blue Cross recommends veterinary advice for a puppy that is vomiting, and current veterinary guidance generally advises greater caution with very young animals.

If your puppy is repeatedly sick, lethargic, has diarrhoea, refuses food or water or simply does not seem right, contact your veterinary practice.

What about an older dog?

I also take vomiting more seriously in an older dog, particularly when it is new, recurrent or accompanied by another change.

For example:

• reduced appetite
• weight loss
• increased drinking
• unusual urination
• lethargy
• discomfort
• weakness
• behavioural change

Vomiting can occur with kidney, liver and pancreatic disease as well as gastrointestinal problems, so persistent vomiting in an older dog deserves veterinary assessment.

How can I reduce the chance of my dog getting an upset stomach?

You cannot prevent every episode of vomiting, but you can reduce some common risks.

I would:

• keep bins and food waste secure
• keep medicines and household chemicals out of reach
• avoid giving heavily seasoned or fatty leftovers
• check treats and foods for potentially toxic ingredients
• change diets gradually
• replace damaged toys before pieces can be swallowed
• prevent access to cooked bones and unsafe objects
• pay attention to scavenging on walks
• know what is normal for your individual dog

Some dogs are determined scavengers.

If scavenging presents a genuine health risk, a properly fitted basket muzzle can sometimes be useful when introduced positively and appropriately. A muzzle should allow the dog to pant, drink and take treats. It should not be used as punishment.

What I notice when walking a dog one-to-one

One advantage of walking one dog at a time is that I get to know what is normal for that individual.

If a dog who normally sets off enthusiastically through Finchley or Coldfall Wood suddenly slows down, refuses treats, starts swallowing repeatedly, seems uncomfortable, or simply does not look right, I can notice that change.

I am not trying to diagnose the dog.

I can shorten or stop the walk, get them home safely, contact their owner and recommend veterinary advice where appropriate.

That ability to notice small changes is one reason I prefer calm, one-to-one dog walking over transporting groups of dogs in a van.

Looking for individual dog walking in Finchley? My Solo Dog Walks are one household at a time, starting and finishing at your dog’s own home.

Frequently asked questions

Is it normal for a dog to be sick occasionally?

An otherwise healthy adult dog may occasionally vomit once and then appear completely normal.

Monitor them carefully.

If vomiting continues, another symptom develops or something simply does not seem right, contact your vet.

Why is my dog vomiting yellow foam?

Yellow or green foamy vomit often contains bile.

It does not, by itself, tell you why your dog is vomiting.

If it happens repeatedly, discuss it with your vet rather than assuming your dog simply needs to eat more often.

Should I feed my dog immediately after they vomit?

If an otherwise healthy adult dog has vomited once and seems well, current PDSA advice supports small portions of an easily digestible, low-fat diet rather than automatically withholding food for a prolonged period.

Individual circumstances differ, so ask your vet if you are unsure. (PDSA)

Should I give my dog water after vomiting?

Yes, hydration is important.

Offer water little and often. If your dog cannot keep water down or continues vomiting, contact your vet. (PDSA)

When is vomiting an emergency?

Repeated unsuccessful retching with a swollen abdomen, collapse, severe pain, suspected poisoning and a seriously unwell dog require urgent veterinary attention.

Blood in vomit, repeated vomiting, dehydration and marked lethargy also warrant veterinary advice. (PDSA)

Can I make my dog sick if they have eaten something poisonous?

Do not try to make your dog vomit at home.

Contact your vet or Animal PoisonLine and follow their instructions.

The main thing to remember

A dog being sick once does not automatically mean there is an emergency.

But vomiting is not something to diagnose from the colour of the liquid or treat automatically with whatever happens to be in the kitchen cupboard.

Look at the whole dog.

Notice how often it is happening.

Watch for changes in behaviour, pain, hydration, and other symptoms.

And if you are concerned, phone your vet.

You do not need to know what is wrong before asking for help.

Related Guides

• Dog Health & First Aid Guide
• When Should I Call the Vet?
• Dog Food & Nutrition Guide
• How Do I Change My Dog’s Food?
• Can Dogs Eat Human Food?

Veterinary disclaimer

I am a professional dog walker and hold an Ofqual Level 3 qualification in Canine First Aid. I am not a veterinary surgeon.

This guide is intended to help dog owners recognise changes and understand when they may need veterinary advice. It cannot diagnose the cause of vomiting and does not replace advice from your veterinary practice.

If your dog is unwell, symptoms persist or worsen, or you are concerned, contact a qualified veterinary professional. In an emergency, contact your veterinary practice or nearest emergency veterinary provider immediately.

• Why do dogs eat grass? Real reasons and when to worry
• Dog-Friendly Vegetables – What Vegetables Can Dogs Eat?
• Dogs and Plants: Toxic and Non-Toxic
• Hidden Dangers on Dog Walks:
• When Should I Call the Vet?