Bloody Gastrointestinal Inflammation in Dogs (Acute Hemorrhagic Gastroenteritis)

  • Synonyms: Acute Hemorrhagic Diarrhea Syndrome, AHGE, Hemorrhagic Gastroenteritis, HGE, Acute Hemorrhagic Diarrhea Syndrome (AHDS)
  • Occurrence: common
  • Location of disease: Abdomen/pelvis
Author: Dr. med. vet. Gisa Löwe | Last modified: 23.08.2026
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Urgent see a veterinarian within 24 hours

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If the condition worsens / symptoms persist, consult a veterinarian.

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An interesting overview of gastrointestinal problems in dogs, supplemented by information on the intestinal microbiome and the importance of probiotics, can be found here:

Magen-Darm-Probleme beim Hund

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Definition

Acute Hemorrhagic Gastroenteritis (AHG) is a sudden digestive disease in dogs characterized by severe, bloody diarrhea and frequent Vomiting. This disease can quickly lead to dangerous Fluid loss (dehydration) and often requires immediate veterinary treatment.

The most important facts at a glance

Acute hemorrhagic gastroenteritis is a life-threatening, sudden intestinal inflammation that manifests in dogs through Vomiting and bloody Diarrhea. Rapid diagnosis, optimal fluid and electrolyte management, and an adapted diet are the central pillars of therapy. Thanks to intensive research and modern diagnostics, there are good chances of successful treatment, provided therapy is initiated early.

Causes

Acute Hemorrhagic Gastroenteritis is a disease of the gastrointestinal tract primarily caused by Inflammatory conditions of the mucous membranes in the stomach and intestines. This inflammation leads to increased permeability of blood vessels, resulting in the leakage of fluids and red blood cells into the intestine. This explains the bloody diarrhea, which is a characteristic symptom of the disease.

Scientifically, it is believed that a combination of viral, bacterial, and possibly parasitic infections could play a role in the development of the disease. Stress and a sudden change in diet are also considered possible triggers. Additionally, a disturbed immune response of the body may be involved in some cases.

Some specific bacteria, such as Clostridium perfringens, are often associated with AHG. These bacteria can produce toxins that damage the intestinal lining. Viral infections like parvovirus and coronavirus could also affect the intestinal lining and lead to similar symptoms. However, the exact cause is often not clearly identifiable.

Symptoms

Rare symptoms:

The most common symptoms of acute hemorrhagic gastroenteritis are sudden, severe, and often bloody Diarrhea. This can be accompanied by severe Vomiting. Affected dogs often show signs of discomfort, such as Abdominal pain, loss of appetite, and lethargy.

Due to significant Fluid loss (dehydration), dehydration and electrolyte imbalances frequently occur. In severe cases, circulatory shock can develop, which becomes life-threatening if not treated quickly. Fever and pale gums can also be signs of the severity of the disease.

Typical is the very rapid course with severe Fluid loss (dehydration).

 

Therapy

The treatment of acute hemorrhagic gastroenteritis focuses on stabilizing the dog and treating the symptoms. Fluid therapy is crucial to compensate for Fluid loss (dehydration) and electrolyte imbalance. Intravenous fluids are often administered to ensure rapid rehydration.

In addition, antiemetic and antidiarrheal medications can be used to relieve symptoms and stabilize bowel function. Antibiotics may be considered if a bacterial infection is suspected or if there is a risk of secondary infections.

In severe cases, inpatient treatment at a veterinary hospital may be necessary to ensure optimal monitoring and care. The diet is often switched to easily digestible food to relieve the digestive tract.

Prognosis and follow-up care

The prognosis for dogs with acute hemorrhagic gastroenteritis is generally good if the disease is detected and treated early. Most dogs recover completely within a few days after treatment begins.

Untreated, however, the disease can have serious consequences, including Cardiovascular collapse and Death. Therefore, it is important to act quickly at the first signs of AHG and seek veterinary help.

The long-term outlook is positive, and relapses are rare if the underlying causes are identified and treated. However, careful follow-up and monitoring are required to ensure complete recovery.

Prevention

Prevention of acute hemorrhagic gastroenteritis includes a balanced and consistent diet to avoid sudden changes in the digestive tract. Stress reduction and careful monitoring of the dogs’ environment can also help minimize the risk.

Regular veterinary checkups and vaccinations are important to detect and treat infections and other health problems early. Hygiene measures such as cleaning food and water bowls can help prevent the spread of pathogens.

It is advisable to keep dogs away from potentially contaminated environments and to pay attention to drinking water quality. A switch to new food should be done gradually to avoid overwhelming the digestive tract.

Outlook on current research

Current research focuses on the role of the intestinal microbiome and the significance of Clostridium perfringens in the pathogenesis of AHG. Modern molecular detection methods such as quantitative PCR and next-generation sequencing are intended to help better identify pathogenic organisms. New immunomodulatory therapies or probiotic approaches are being investigated to stabilize the intestinal barrier. The influence of diet on the microbiota and the regeneration of the intestinal lining is also the subject of intensive research.

Frequently Asked Questions (FAQs)

1. What exactly is HGE?
HGE stands for acute hemorrhagic gastroenteritis. In dogs, it manifests as sudden bloody Diarrhea and Vomiting. According to Ettinger and Feldman (Textbook of Veterinary Internal Medicine), this is considered an emergency, as massive fluid loss can occur.
2. Is HGE contagious to other dogs?
In many cases, no classic infection, such as with viral Diarrhea diseases, is observed. Nevertheless, close Contact with other dogs should be restricted if bacterial co-causes are suspected. On petsvetcheck.de, it is recommended to adhere to hygiene and feeding management particularly carefully.
3. How quickly should I go to the vet?
If HGE is suspected, an immediate visit to the vet is advisable. Even short delays can worsen the dog's health, as there is a risk of circulatory collapse.
4. Can I help the dog at home?
In uncomplicated cases, a bland diet and sufficient fluid intake can bring relief. However, with clear symptoms (bloody Diarrhea, severe Vomiting), clinical treatment is indispensable.
5. Is an antibiotic always used?
Not in every case. Antibiotics are administered when bacterial overgrowth or severe co-infections are suspected. The vet decides based on blood counts and clinical findings.
6. What role does diet play in HGE?
Dietary changes or unfamiliar food can be triggers. A light, easily digestible diet supports recovery after Vomiting is controlled. Some experts recommend special diets to relieve the intestines.
7. Is follow-up care important after recovering from HGE?
Regular checks of blood values and observation of eating and defecation behavior are useful to detect relapses early.
8. Can certain breeds be more frequently affected?
There are indications that toy and miniature breeds are more frequently affected by HGE, but the disease can, in principle, affect any dog. The exact reasons for this have not been conclusively clarified.
9. What happens if the dog remains untreated?
Untreated HGE can lead to severe dehydration, electrolyte imbalances, and circulatory failure. In acute cases, there is a life-threatening risk. An immediate vet visit is therefore essential.
10. Is a recurrence of HGE possible?
Yes, relapses cannot be ruled out. Factors such as Stress, changes in diet, or infections can trigger AHG again. A stable intestinal flora / gut microbiota and careful feeding regimens reduce the risk.

Literature

  • Wessely, V., Suchodolski, J. S., Cavasin, J. P., Holz, M., Busch-Hahn, K., & Unterer, S. (2025). Prevalence of Clostridium perfringens encoding the netF toxin gene in dogs with acute and chronic gastrointestinal diseases. Pets, 2(1), Article 9. https://doi.org/10.3390/pets2010009
  • Reisinger, A., Stübing, H., Suchodolski, J. S., Pilla, R., Unterer, S., & Busch, K. (2024). Comparing treatment effects on dogs with acute hemorrhagic diarrhea syndrome: Fecal microbiota transplantation, symptomatic therapy, or antibiotic treatment. Journal of the American Veterinary Medical Association, 262(12), 1657–1665. https://doi.org/10.2460/javma.24.03.0153
  • Reisinger, A., Stübing, H., Ishii, P. E., Suchodolski, J. S., Lidbury, J. A., Busch, K., & Unterer, S. (2024). Evaluation of intestinal barrier dysfunction with serum iohexol concentration in dogs with acute hemorrhagic diarrhea syndrome. Animals, 14(6), Article 963. https://doi.org/10.3390/ani14060963
  • Jugan, M. C., KuKanich, K., & Freilich, L. (2023). Clinical response in dogs with acute hemorrhagic diarrhea syndrome following randomized probiotic treatment or fecal microbiota transplant. Frontiers in Veterinary Science, 10, Article 1050538. https://doi.org/10.3389/fvets.2023.1050538
  • Unterer, S. (2021). Acute hemorrhagic diarrhea syndrome in dogs. Veterinary Clinics of North America: Small Animal Practice, 51(1), 79–92. https://doi.org/10.1016/j.cvsm.2020.09.007
  • Dupont, N., Jessen, L. R., Moberg, F., Zyskind, N., Lorentzen, C., & Bjørnvad, C. R. (2021). A retrospective study of 237 dogs hospitalized with suspected acute hemorrhagic diarrhea syndrome: Disease severity, treatment, and outcome. Journal of Veterinary Internal Medicine, 35(2), 867–877. https://doi.org/10.1111/jvim.16084
  • Sindern, N., Suchodolski, J. S., Leutenegger, C. M., Mehdizadeh Gohari, I., Prescott, J. F., Proksch, A. L., Mueller, R. S., Busch, K., & Unterer, S. (2019). Prevalence of Clostridium perfringens netE and netF toxin genes in the feces of dogs with acute hemorrhagic diarrhea syndrome. Journal of Veterinary Internal Medicine, 33(1), 100–105. https://doi.org/10.1111/jvim.15361
  • Ziese, A.-L., Suchodolski, J. S., Hartmann, K., Busch, K., Anderson, A., Sarwar, F., Sindern, N., & Unterer, S. (2018). Effect of probiotic treatment on the clinical course, intestinal microbiome, and toxigenic Clostridium perfringens in dogs with acute hemorrhagic diarrhea. PLOS ONE, 13(9), Article e0204691. https://doi.org/10.1371/journal.pone.0204691
  • Unterer, S., Lechner, E., Mueller, R. S., Wolf, G., Straubinger, R. K., Schulz, B. S., & Hartmann, K. (2015). Prospective study of bacteraemia in acute haemorrhagic diarrhoea syndrome in dogs. Veterinary Record, 176(12), 309. https://doi.org/10.1136/vr.102521
  • Mortier, F., Strohmeyer, K., Hartmann, K., & Unterer, S. (2015). Acute haemorrhagic diarrhoea syndrome in dogs: 108 cases. Veterinary Record, 176(24), 627. https://doi.org/10.1136/vr.103090