June 13, 2025, 12:06 pm | Read time: 5 minutes
Diarrhea is unpleasant for both humans and animals. Naturally, pet owners want to help their four-legged friends quickly. But are there dog breeds more prone to diarrhea? And why do veterinarians still prescribe antibiotics so readily? A study has investigated this.
Acute diarrhea is not only unpleasant for dogs but also one of the most common reasons for a vet visit. A large-scale British study now shows: One in twelve dogs is treated annually for acute diarrhea—usually very successfully. Based on the data, researchers were also able to determine which animals have a more sensitive digestive system and found clear correlations to diarrhea in mixed breeds, purebreds, and designer dogs. The data also revealed which animals are least likely to end up with diarrhea in a veterinary practice. However, another detail raises eyebrows: Despite clear recommendations against it, many dogs still receive antibiotics—often without a genuine medical reason.
Diarrhea in Dogs Not Always an Independent Diagnosis
Diarrhea is among the most common symptoms in dogs at veterinary practices—yet it is often not recorded as an independent diagnosis. Estimates suggest that only about one-third of affected dogs are ever presented to a vet. Previous studies reported prevalence rates between 2.2 and 3.8 percent.
The current study, however, reports significantly higher values. Although acute diarrhea is usually self-limiting—meaning it is limited by certain factors or time—antibiotics are frequently prescribed. This is despite growing criticism and fear of antibiotic resistance.
A European expert commission and British national guidelines clearly advise against the use of antibiotics in mild and moderate cases. Nevertheless, their use remains widespread, often driven by veterinarians’ fear of not meeting owners’ expectations. This discrepancy between clinical reality and medical evidence was the starting point of the study.
Diarrhea in Dogs More Common Than Thought—But Treatable
The study by the Royal Veterinary College (RVC) in collaboration with the Willows Veterinary Centre examined the treatment of acute diarrhea in dogs. The analysis used the VetCompass database, which collects electronic health data from veterinary practices in the United Kingdom. A cross-section from 2019 was analyzed, focusing on newly occurring, uncomplicated acute diarrhea events.
In total, the initial cohort included 2,250,417 dogs. Through text searches, over 800,000 suspected cases were identified, of which 8,053 were manually reviewed. The study was published on June 11, 2025, in the journal “PLOS ONE.” The aim was to scientifically investigate the frequency, risk factors, and treatment patterns of this widespread condition in everyday veterinary practice.
1,835 cases met the criteria and were classified as “acute diarrhea” in mixed breeds, purebreds, and so-called designer dogs. An incident was considered “acute” if no diarrhea was documented in the previous 30 days and no other overarching diagnosis (e.g., infection or poisoning) was made. The analysis also considered information on breed, age, gender, weight, accompanying symptoms, and treatment methods.
Designer Dogs More Often Treated for Diarrhea
The estimated annual incidence rate for acute diarrhea was 8.18 percent—significantly higher than previously assumed. However, in 80.27 percent of cases, a single vet visit was sufficient. The most common accompanying symptoms were vomiting (44.25%), loss of appetite (27.68%), and lethargy (24.20%). Bloody diarrhea was documented in 29.32 percent of cases.
Despite contrary recommendations, 38.2 percent of dogs received antibiotics—even 58.55 percent in cases of bloody diarrhea. The most commonly administered drugs were Metronidazole (65.19%), followed by Amoxicillin. The most used other treatments were probiotics (59.62%), dietary management (43.98%), and the antiemetic Maropitant (24.03%).
To see which dogs have an increased risk of diarrhea, mixed breeds were used as a starting point, and the incidence was calculated from there. Six breeds showed an increased risk in comparison:
- Maltese and
- Miniature Poodle,
- Cavapoo,
- German Shepherd,
- Yorkshire Terrier and
- Cockapoo.
The risk was also significantly higher in very young (<3 years) and older (>9 years) dogs. Neutered or spayed animals had a 25 percent higher risk compared to intact dogs.
Diarrhea Remains a Central Issue for Veterinarians and Owners
Borderline correlations were also observed in Cavalier King Charles Spaniel, Labradoodle, Golden Retriever, and English Bulldog. Diarrhea was significantly less common in Chihuahua and Jack Russell Terrier, but the French Bulldog, Husky, and Patterdale Terrier also ranked low.
This study provides the first comprehensive insights into the management of acute diarrhea in everyday veterinary practice. The high incidence shows that diarrhea remains a central issue for veterinarians and owners. Notably, over 80 percent of dogs required only a single visit—an indication that the prognosis under veterinary care is generally very good.
Researchers Warn About Diarrhea in Designer Dogs
Nevertheless, the frequent use of antibiotics is concerning. This is in clear contradiction to current guidelines and could contribute to the development of antibiotic resistance. The identified risk groups—certain breeds as well as very young and older animals—provide an important basis for more targeted prevention and education.
Additionally, the results show that so-called designer dogs are apparently particularly often affected by diarrhea, which should prompt breeders and future owners to reconsider.
The study is based on electronic health data from 2019 and mainly reflects the practice standards of large veterinary chains, not necessarily the entire spectrum of British veterinary medicine. However, the datasets are also comprehensive and very informative. They offer a more comprehensive picture than is possible in many other countries without corresponding digitization. Moreover, veterinary health care in the United Kingdom is comparable to much of the developed world, so the data can also be applied in Germany.
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Conclusion
This comprehensive study shows: Acute diarrhea is widespread in dogs, usually harmless–and yet often treated with antibiotics, even though this is medically unnecessary in many cases. For veterinarians and owners, this means: More trust in supportive therapies like diet and probiotics and fewer “safety prescriptions” with antibiotics. Future educational efforts should particularly target owners of at-risk breeds, designer dogs, and age groups predisposed to diarrhea. 1