SIBO in Dogs: What It Is and How To Help Your Pet

While pet parents are often familiar with diarrhea in dogs and may have even heard of SIBO in people, they may not know about SIBO in dogs.  

Small intestinal bacterial overgrowth (SIBO) in dogs can cause significant diarrhea and poor absorption of nutrients.  

Here, you’ll learn about symptoms of SIBO in dogs, causes of this condition, and how veterinarians handle canine SIBO. 

What Is SIBO in Dogs?

SIBO is the acronym for small intestinal bacterial overgrowth. A dog’s normal gut bacteria within the small and large intestines are important for their digestive health and immune system. 

When a dog has SIBO, there are too many bacteria in the small intestine. These bacteria compete with the animal for nutrients in digested food and can also cause damage to the surface of the intestines.  

The small intestine does most of the nutrient absorption. When the surface of the small intestine is damaged, nutrients from digested food cannot be properly taken in by the body. This results in chronic diarrhea that can last weeks to months without treatment. 

SIBO in dogs is also called antibiotic-responsive diarrhea (ARD) or small intestinal dysbiosis. 

SIBO in dogs is not usually a medical emergency, but seek emergency care in the following scenarios: 

• Your dog’s diarrhea is accompanied by uncontrolled vomiting. 
• Diarrhea is severe. 
• There is blood in the diarrhea. 
• Your dog is dehydrated, weak, or lethargic. 
• Your dog is a young puppy or an unvaccinated adult.  

Symptoms of SIBO in Dogs

The following are symptoms of SIBO in dogs: 

• Watery, chronic diarrhea 
• Weight loss 
• Normal or increased appetite 
• Flatulence and bloating 
• Pica or stool eating 

SIBO in dogs is not usually accompanied by vomiting.  

If your dog is vomiting or loses their appetite, SIBO is less likely to be the cause of your dog’s symptoms. 

Causes of SIBO in Dogs

It’s common for the cause of SIBO to be unknown.  

SIBO can also happen with other conditions, including: 

• Exocrine pancreatic insufficiency (EPI) 
• Inflammatory bowel disease (IBD) 
• Conditions causing long-term inflammation (swelling) in the intestines, like food allergies 

There may be a genetic component to the development of SIBO, as German Shepherds may be more likely to get the condition. 

How Veterinarians Diagnose SIBO in Dogs

The veterinarian will likely recommend the following diagnostics: 

• Routine blood work and urine testing: Most of the time, these tests will be relatively normal in dogs with SIBO, but they’re important for finding systemic health issues. 
• Cobalamin (vitamin B12)/folate/trypsin-like immunoreactivity (TLI): Folate levels may be high while B12 amounts are low. This pattern can also happen in dogs with EPI. Some dogs with poor nutrient absorption will have reduced levels of both B12 and folate. If TLI is low, EPI will likely be the diagnosis, either on its own or with SIBO. 
• Fecal testing: The veterinarian may test the feces to rule out parasites or other infectious diseases. Culture of feces is usually not helpful for diagnosis of SIBO. 
• Abdominal imaging: Abdominal X-rays or ultrasound may show changes to the size or structure of the organs in the abdomen. Ultrasound can also let the vet check the intestinal lining. 
• Antibiotic trial: If SIBO is suspected, an antibiotic trial may be recommended as both a diagnostic and therapeutic. If there is a good response to the antibiotic, SIBO may be diagnosed. 
• Dietary trial: Some chronic diarrheas respond to dietary changes, such as the use of a hypoallergenic or high-fiber diet. Like antibiotics, these may be recommended as both a diagnostic and a therapy. 
• Intestinal biopsy: While biopsies of the intestines are unlikely to diagnose SIBO, they may find contributing factors like IBD. 

Make sure to let the veterinarian know the following information: 

• Your dog’s current diet and any recent dietary changes 
• History of dietary indiscretion (your dog eating things they shouldn’t) 
• Any medications, supplements, or probiotics your dog takes 
• How long the symptoms have been going on 
• Vaccine and parasite prevention history 

Make sure to speak with the veterinarian about whether they’ll want your dog fasted and if they’ll want you to bring in a stool sample for your dog’s appointment. 

Treatment of SIBO in Dogs

SIBO in dogs is usually treated with a long-term course of antibiotics.  

Antibiotics commonly used include tylosin, oxytetracycline, and metronidazole.  

These antibiotics are usually given four to six weeks.  

If cobalamin is low, the dog should have this supplemented via injection. These injections can be given under the skin, usually once weekly during treatment. If there is an underlying cause for the dog’s SIBO, such as EPI, the dog may continue to need monthly cobalamin injections.  

Probiotics, such as Purina FortiFlora, may be recommended to help re-establish normal bacteria within the intestines, especially after antibiotics have been given. 

If a dietary change is recommended, the veterinarian may suggest a veterinary diet, such as Hill’s Gastrointestinal Biome or Royal Canin Hydrolyzed Protein.  

These will usually be either hydrolyzed-protein or high-fiber diets. 

EPI and other underlying causes of SIBO may need lifelong management. 

Recovery and Management of SIBO in Dogs

Most dogs with SIBO show a big improvement after two weeks of antibiotic treatment. If this isn’t the case, the veterinarian will need to consider more diagnostics to rule out other health conditions or underlying causes for the dog’s symptoms. 

If signs improve during treatment but recur once the antibiotics are stopped, the dog will also need further diagnostics to rule out underlying causes.  

Conditions like EPI or IBD will need lifelong management. 

Prevention of SIBO in Dogs

There isn’t a known way to prevent SIBO. Most cases occur with no known cause.   

You can help keep your dog healthy by providing them with a high-quality diet and keeping up on their parasite prevention. Regular veterinary care is important for detecting issues early.