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Useful information about the needs of cats and dogs with nutritionally sensitive health conditions.

Gastrointestinal Disorders

Fiber-Responsive Colitis and Large Bowel Diarrhea in Dogs

Fiber-responsive diarrhea in dogs can be an inflammatory (e.g., colitis) or non-inflammatory (e.g., chronic idiopathic large bowel diarrhea) condition that primarily affects the colon and clinically improves after fiber is added to the diet.1─3 Both colitis and idiopathic large bowel diarrhea are characterized by soft-to-liquid stools often combined with excess mucus and/or fresh red blood, tenesmus, and increased defecation frequency and urgency.1─5 Colitis may be acute or chronic with intermittent or persistent diarrhea.

The goals of dietary intervention are to reduce or eliminate clinical signs while meeting a dog’s nutritional needs.

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Did You Know? Fact Highlight

Approximately 95% to 99% of the short-chain fatty acids (SCFAs) produced by bacterial fermentation are rapidly absorbed in the large intestine, where colonocytes use them as an energy source.6 SCFAs also aid water and electrolyte absorption.

Key Messages

  • A key nutritional consideration for these cases is to increase dietary fiber, while still feeding a diet made with highly digestible protein, fat, and carbohydrate ingredients. 
    • Increased dietary fiber influences stool consistency, normalizes colon motility, and improves SCFA production. 
    • Highly digestible macronutrients help reduce colon irritation and prevent maldigestion. 
  • Most dogs with fiber-responsive colitis or large bowel diarrhea can benefit from a combination of soluble (fermentable) and insoluble (poorly fermentable) fibers.1─5,8 
    • Dietary fiber can be categorized by solubility and fermentability.7,9 
    • Soluble, gel-forming fiber adsorbs large amounts of water, which improves stool consistency and supports normal colon motility. 
    • Soluble fiber is metabolized by the microbiota, producing SCFAs that colonocytes use for energy while also reducing the pH of colon contents, decreasing toxin absorption, and potentially inhibiting the growth of pathogenic bacteria. 
    • Insoluble dietary fiber increases stool bulk, improving intestinal motility and normalizing transit time, while also binding water to form a firmer stool. 
    • Insoluble fiber binds unabsorbed bile acids and microbial toxins, which helps protect the colonic mucosa from injury. 
  • Another nutritional strategy that may benefit dogs with fiber-responsive diarrhea is the administration of prebiotics, probiotics or synbiotics
    • Prebiotics, specific soluble fibers that are fermented by bacteria in the colon, can help recover beneficial bacterial populations, restore short-chain fatty acid production and lower intestinal lumen pH. 
    • A probiotic supplement, particularly one with immune-modulating and anti-inflammatory effects, can positively influence the gut microbiome and intestinal health. 
    • Synbiotics, which blend probiotics and prebiotics, may provide complementary or synergistic benefits for gut health. In complementary combinations, the prebiotic and probiotic have independent mechanisms and benefits.10  
  • For dogs that do not respond to increased dietary fiber and/or probiotics, a hydrolyzed or novel protein diet should be considered.11 
conversation starter background image

“Based on your dog’s evaluation, I suspect your dog may benefit from a change in [his/her] food. I recommend we start [dog’s name] on a therapeutic diet that contains more fiber to see if the additional fiber helps your pet. I am also recommending that [dog’s name] be given a [probiotic/synbiotic] to support [his/her] gut microbiome. We should see improvement within 2 weeks and, if not, we can discuss trying a hydrolyzed or novel protein diet, which can be helpful in some cases.” 

To Share With Pet Owner:

Managing the Gut Microbiome

Diet, a controllable factor that influences the gut microbiome, offers a daily opportunity to contribute to gut health.

View Brief 1 min to 5 min

Intestinal Dysbiosis in Dogs and Cats

Diet modification is a key component of therapeutic plans for managing dogs and cats with intestinal dysbiosis.

View Brief 1 min to 5 min

Fiber in Pet Food

High fiber diets are often recommended for people to support a healthy digestion. What is the role of fiber in pet foods?

View Hot Topic 6 min to 10 min


Purina was the first to use prebiotics in pet food and is a leader in the field. What are the benefits of prebiotics to pets?

View Hot Topic 6 min to 10 min


Probiotics offer many benefits, but with so many options available, pet owners may not know how to select the best quality and most appropriate one for their pet's needs

View Hot Topic 6 min to 10 min


  1. Leib, M. S. (2016). Fiber-responsive large bowel diarrhea. In L. P. Tilley & F. W. K. Smith, Jr. (Eds.), Blackwell’s five-minute veterinary consult: Canine and feline (6th ed., p. 514). Wiley-Blackwell. 
  2. Leib, M. (2000). Treatment of chronic idiopathic large bowel diarrhea in dogs with a highly digestible diet and soluble fiber: A retrospective review of 37 cases. Journal of Veterinary Internal Medicine, 14(1), 27─32. doi: 10.1111/j.1939-1676.2000.tb01495.x 
  3. Marks, S. L. (2016). Colitis and proctitis. In L. P. Tilley & F. W. K. Smith, Jr. (Eds.), Blackwell’s five-minute veterinary consult: Canine and feline (6th ed., pp. 293─295). Wiley-Blackwell. 
  4. Zoran, D. (2010). Large bowel diarrhea–canine. In Nestlé Purina PetCare handbook of canine and feline clinical nutrition (pp. 46─47). Nestlé Purina PetCare Company. 
  5. Campbell, S. (2010). Colitis–canine. In Nestlé Purina PetCare handbook of canine and feline clinical nutrition (pp. 52─53). Nestlé Purina PetCare Company. 
  6. Von Engelhardt, W., Rönnau, K., Rechkemmer, G., & Sakata, T. (1989). Absorption of short-chain fatty acids and their role in the hindgut of monogastric animals. Animal Feed Science and Technology, 23(1─3), 43─53. doi: 10.1016/0377-8401(89)90088-6 
  7. Gross, K. L., Yamka, R. M., Khoo, C., Friesen, K. G., Jewell, D. E., Schoenherr, W. D., Debraekeleer, J., & Zicker, S. C. (2010). Macronutrients. In M. S. Hand, C. D. Thatcher, R. L. Remillard, P. Roudebush, & B. J. Novotny (Eds.), Small animal clinical nutrition (5th ed., pp. 49─105). Mark Morris Institute. 
  8. Lenox, C. (2021). Nutritional management for dogs and cats with gastrointestinal diseases. Veterinary Clinics of North America: Small Animal Practice, 51(3), 669─684. doi: 10.1016/j.cvsm.2021.01.006 
  9. Cave, N. (2012). Nutritional management of gastrointestinal diseases. In A. J. Fascetti & S. J. Delaney (Eds.), Applied veterinary clinical nutrition (pp. 175─219). Wiley-Blackwell. 
  10. Cunningham, M., Azcarate-Peril, M. A., Barnard, A., Benoit, V., Grimaldi, R., Guyonnet, D., Holscher, H. D., Hunter, K., Manurung, S., Obis, D., Petrova, M. I., Steinert, R. E., Swanson, K. S., van Sinderen, D., Vulevic, J., & Gibson, G. R. (2021). Shaping the future of probiotics and prebiotics. Trends in Microbiology, 29(8), 667─685. doi: 10.1016/j.tim.2021.01.003 
  11. Allenspach, K., Wieland, B., Gröne, A., & Gaschen, F. (2007). Chronic enteropathies in dogs: Evaluation of risk factors for negative outcome. Journal of Veterinary Internal Medicine, 21(4), 700─708. doi: 10.1111/j.1939-1676.2007.tb03011.x