The 11 most common causes for bloody diarrhea in dogs
There is not the one Cause of bloody diarrhea Causes are very diverse. I can reassure you in one respect: Although the vast majority of cases require rapid treatment, but are not acutely life-threatening.
Below you will find a brief overview of them most common ailments, which are associated with bloody diarrhea.
Acute hemorrhagic diarrhea syndrome
This is a common cause of bloody diarrhea in dogs Acute hemorrhagic diarrhea syndrome (AHDS), which particularly affects adult animals. What is characteristic of them is that the health of the four-legged friend is rapidly deteriorating – within a few hours He excretes a lot of blood through his stool, often accompanied by bloody vomiting.
The exact cause of AHDS is still unknown, Researchers suspect, among other things, that a bacterial infection or intolerance could be behind the disease. Smaller dog breeds are mostly affected; the condition occurs more frequently in the cold season.
Fortunately, that is Prognosis for AHDS comparatively well, in many cases the disease disappears as quickly as it appeared. However, it is still an emergency because the heavy bleeding combined with fluid loss can, among other things
- severe dehydration symptoms
- excessive blood loss
- Blood poisoning (sepsis) or also
- Multiple organ failure
appear. The veterinary treatment usually includes infusions to stabilize fluid balance and the administration of medication. The doctor will usually order a blood analysis; elevated hematocrit values are typical for AHDS.
The name is still in use “Hemorrhagic gastroenteritis syndrome”. However, this term is misleading and is generally considered outdated because it is not gastritis in the classic sense.
Giardia
Giardia are highly contagious protozoa that can affect all dogs: as of 2025, a vaccine has not yet been approved; they are transmitted primarily through feces that the four-legged friends sniff and through contaminated water.
Since the parasites settle in the small intestine and cling to the intestinal wall, the diarrhea is usually hbright red and bloody. In dogs with good general health, the infestation usually goes unnoticed for a long time – but due to the high risk of infection, action must be taken here too.
For Puppies, young animals, seniors and dogs with weakened immune systems However, Giardia are quite dangerous and, if the protozoa multiply too much, lead to, among other things, chronic, bloody diarrhea. The vet can detect Giardia using a stool analysis and take action against it antiparasitic drugs.
worms
Some too worms act as intestinal parasites and cause bloody diarrhea. The pests are mainly transmitted to other dogs through feces. If a pregnant dog is affected, the puppies can also be infected from birth.
Help both for prevention and for acute infestations Worm treatments – Since these are sometimes only effective against certain parasites, you should also consult a veterinarian if there are bloody stools.
Bloody diarrhea after Feed change
Diarrhea is a common companion of Feed changes. The stool is rarely bloody. This may be due to irritation of the digestive tract Switch from wet to dry food A lack of fluids can also contribute.
irritations of the intestine
Irritation of the intestines does not only occur due to allergic reactions, but can also have other reasons: the dog often has this ate something indigestible, e.g. gravel, coarse sand or even small parts made of plastic or metal.
These sharp parts can perforate the intestinal walls, at the same time the body notices that something is wrong and tries to force the foreign body out – this then causes diarrhea. Both factors together lead to a reddish color.
Diarrhea usually stops once the problem is resolved. The intestinal walls should also heal quickly in healthy dogs.
Pancreatitis
One Pancreatitis is an inflammation of the pancreas, which is always an emergency and must be treated immediately by a vet. You can find more information here.
One of the most common symptoms is diarrhea, often accompanied by vomiting. The reason for this is that digestion is so disturbed that the gastrointestinal tract cannot process the food eaten in any other way.
This diarrhea is usually not bloody. However, if the diarrhea persists for a long time, it can happen that Inflammation in the intestines occur, which then in turn leads to small internal bleeding. If this happens, you should to the vet immediately – in an emergency, also calling on the emergency service.
Parvovirus
The Parvovirus is a very insidious pathogen that leads to parvovirus. The viruses are absorbed via droplet infection via the nasal and oral mucous membranes highly contagious and survive for a comparatively long time without a host. It is therefore also possible that the dog becomes infected, for example on a contaminated floor.
In addition to severe fever and physical fatigue, bloody diarrhea is one of the main symptoms of parvovirus. Once the disease has broken out, it is extremely dangerous and often fatal.
Fortunately, dogs can be vaccinated against the virus. However, you should be particularly careful Puppies those for whom vaccination is not yet possible. Furthermore, animals with weakened immune systems, such as seniors, can also become ill if vaccinated.
stress
Occasionally can too stress may be partly responsible for bloody stools: Dogs who are constantly “on power” not only often have a weakened immune system, but are also prone to stomach diseases such as gastritis and ulcers. Both can lead to internal bleeding, which then becomes visible in the feces.
Above all, a lot of peace and love helps against stress. This includes in particular enough sleep, If your four-legged friend is taking a nap, you should definitely not wake him up. For some nervous animals, special food can also lead to improvement.
Poisonings
Make an absolute emergency Poisonings represents: If the dog has eaten something that is toxic to him – this includes, for example, chocolate, certain types of fruit and vegetables and of course rat poison or insecticides – this is actually always life-threatening.
On the one hand, the toxins damage the four-legged friends' veins, which then burst and cause severe internal bleeding. On the other hand, the body tries to eliminate the toxins as quickly as possible, which then leads to diarrhea and nausea.
If you suspect poisoning, you must go to the vet immediately! Meanwhile, for toxins taken orally, charcoal tablets can be administered as first aid.
tumordiseases
Also Tumors often cause internal bleeding. In the intestinal area they also disrupt digestion, so that the food is excreted as quickly as possible through diarrhea.
This can be the case with both benign and malignant intestinal tumors. But you shouldn't worry too much about this: Cancer is only comparatively rarely responsible for bloody stools in dogs, Much more often it is due to other, more treatable illnesses or complaints.
reaction to Medication
But occasionally they can too Medication be responsible for the stomach and intestines reacting with bleeding. If you present your four-legged friend to the emergency veterinary service, you must provide the treating doctor with complete information about which medications your dog is taking.
In order to be prepared for such side effects, it is also highly advisable to take the first dose Package leaflet to study carefully.
What what can I do for bloody diarrhea?
If you discover blood in your pet's stool, you may initially be worried. Nevertheless, you must and are allowed to remain calm don't panic. That would only stress the four-legged friend unnecessarily and is no help – loving words and petting are definitely the better solution.
An immediate visit to the vet is an absolute must: Only an expert can provide competent information about the exact cause; quick treatment measures make it more likely that everything will go smoothly.
In the meantime, there are a few things you can do to prevent your loved one's health from deteriorating further.
feeding temporarily set
An important rule of thumb is: If the dog has diarrhea, he should not be given anything to eat at first. The reason for this is that the gastrointestinal tract should not be put under additional strain if it cannot cope with the food.
However, such a “zero diet” should only be carried out for a very short time: it is generally assumed that a dog maximum 24 hours without solid food can be fed, even less for smaller breeds.
For you, this means that you really have to make the next possible appointment to take your four-legged friend to the doctor.
Lots of water against dehydration
However, the dog cannot survive completely without food during this time: if there is diarrhea – regardless of whether it is bloody or not – the animal definitely needs it a lot of liquid.
Otherwise, during diarrhea the dog is at risk of becoming dehydrated. You therefore have to give him a lot to drink; electrolyte solutions or boiled water with a little salt or glucose have also proven effective here.
Quiet the poop regard
This also includes one calm observation of the feces. Bloody diarrhea is not the same as bloody diarrhea; the color and shape allow some conclusions to be drawn about the possible causes:
- Bright red poop indicates fresh blood in the stool. In most cases, this means that the bleeding is coming from the colon. Often – but not always – this indicates a relatively harmless, easily treatable cause.
- Dark poop, which often even looks tarry-black, is usually a sign of bleeding in the small intestine or stomach. In this case, you should be much more alarmed and consider calling a veterinary emergency service, as the causes are often much more serious and sometimes require immediate action.
Also Photos can be helpful: Some veterinarians use messenger services, then you can send pictures of the feces and often receive a competent initial assessment.
If poisoning is suspected: Charcoal tablets
If you suspect that your dog may have consumed poison, you should definitely tell the dog Charcoal tablets give. They act like a sponge in the body and reliably absorb toxic substances that have not yet been processed and can save the life of your four-legged friend.
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