Gastroenteritis and Colitis in Dogs and Cats

 Gastroenteritis and colitis are common conditions seen in veterinary practice.   These conditions can be tricky to manage, and a quick response to the signs and symptoms of these disorders is critical.  Knowing the causes of these diseases can reduce the risk of contracting them in the first place.  


What is gastroenteritis and colitis?

Gastroenteritis is inflammation of the gastrointestinal tract (the stomach and intestines).  It is often caused by poor nutrition and low-quality food; however, bacteria, viruses, parasites, and medication side effects can also cause these conditions. Colitis is a medical term that specifically describes inflammation of the colon, or large intestine.


What are the signs and symptoms of gastroenteritis and colitis? 

Most cats and dogs with gastroenteritis will have intermittent episodes of vomiting and diarrhea. The vomit may contain bile, a foamy, yellowish substance, especially after emptying the stomach.  Tenderness around the abdomen is another sign of gastrointestinal inflammation. Your pet may appear lethargic and have a decreased appetite.  A low-grade fever is common.  Dehydration can occur quickly if vomiting and diarrhea persist for more than 24 hours. 

With colitis, small volumes of semi-formed (or liquid) feces are often seen, along with small amounts of bright red blood passed near the end of defecation.  Dogs and cats with colitis will exhibit urgency and need to defecate frequently.  Vomiting occurs less often (less than 30%) with colitis and weight loss is rare.  The inflammation from colitis results in reduced water absorption and a decreased ability to store feces in the colon.


What are the causes of gastroenteritis and colitis?

The causes of gastroenteritis include:

  • Poor diet or changes in diet, treats, rewards, etc.
  • Compromised gut microbiome.
  • Stress and anxiety – stress colitis is one of the leading causes of large bowel diarrhea in dogs.
  • Internal parasites such as roundworms, whipworms, coccidia and giardia.
  • Bacteria from infection or an abnormal overgrowth of “bad” bacteria (Salmonella, Clostridium, E. coli) that normally inhabit the digestive tract.
  • Foreign bodies or other obstructions.
  • Recent exposure to pesticides, medications, or cleaning agents.
  • Recent vaccinations given to your pet
  • Metabolic diseases such as EPI, thyroid disease, and Addison’s or Cushing’s disease.
  • Tumors in the gastrointestinal tract.
  • Pancreatitis (inflammation of the pancreas.)


How are gastroenteritis and colitis diagnosed?

Gastroenteritis is a diagnosis of exclusion.  Your veterinarian will perform tests that rule out other conditions.  If you suspect gastroenteritis or colitis, note the signs and symptoms, and see your vet within 24 hours of symptom onset.  Other critical information includes:

  • Pet’s current diet, including quantity and frequency of feeding.
  • Everything your pet ate or drank within the past 48 hours.
  • New foods, treats, or rewards.
  • Recent illnesses as well as a complete medical history.
  • Medications, supplements, and vitamins.
  • Recent exposure to pesticides, cleaning agents, new materials, etc.
  • New home? Visiting friends? New walking path? Any change in routine?

Diagnosis will begin with a complete physical examination, including a temperature check to determine if a fever is present.  Additional testing will depend upon the severity and duration of clinical signs, and medical history.  These include:

  • Complete blood cell count (CBC) to detect the presence of dehydration and infection.
  • Serum chemistries and electrolytes to detect organ system abnormalities and electrolyte imbalances.
  • Fecal floatation test to look for the presence of intestinal parasites and fecal culture test to assess the fecal microbiome.
  • Urinalysis to detect urinary tract infections, kidney disease, and/or dehydration.
  • Abdominal X-Rays and/or ultrasound to rule out stomach or intestinal obstruction.
  • Colonoscopy and colon biopsies may be recommended for colitis symptoms.


How are gastroenteritis and colitis treated?

 The specific treatment will vary depending on test results.  Conventional treatment may include:

  • Fasting for 24-48 hours
  • Feeding a low-residue or hypoallergenic/prescription diet. I believe these “foods” do more harm than good.  The FDA admits these foods have not been evaluated for safety and efficacy, and no long-term studies have been performed on these diets.  Highly processed prescription foods are low in nutrition and not effective at healing the gut microbiome. 
  • Antimicrobial drugs may be indicated. These drugs kill both good and bad bacteria and damages the microbiome and the immune system. 
  • Anti-inflammatory or immunosuppressive drugs may be used in cases of inflammatory or immune-mediated colitis. Like antibiotics, steroidal drugs can have negative effects on the microbiome and immune system.
  • Anti-vomiting or anti-diarrheal drugs may also be recommended. These drugs may suppress the symptoms, but they do not eliminate the cause of the symptoms.
  • Antacids have side effects such as constipation, diarrhea, fatigue, nausea, or vomiting. Human drugs such as Pepto Bismal and Pepcid should never be given to dogs or cats.

 Natural and holistic remedies are effective in the treatment of gastroenteritis and colitis.  Their aim is to get at the root cause of the problem and solve it without synthetic drugs.  Managing symptoms can be accomplished with food, herbs, and other alternative therapies such as acupuncture. Gastrointestinal disease has its roots in the diet. From a Traditional Chinese Veterinary Medicine (TCVM) perspective, highly processed commercial diets can exacerbate the problem by creating dampness and phlegm from the substances in the food that the body cannot use.  As energy flow is blocked, friction is released as heat (inflammation).  Vomiting occurs when the downward energy is blocked (spleen qi stagnation).   Gastroenteritis and colitis that stem from stress and anxiety or from fatty or greasy foods can result in liver qi stagnation.

Natural and holistic remedies include:

  • Fasting for 24-48 hours – fasting allows the digestive tract to rest and heal.
  • Hydration – even when fasting, give your pup or kitty plenty of water or bone broth to drink. Bone broth is full of nutrients and minerals. Your veterinarian may also administer sub-q or intravenous (IV) fluids to help with severe dehydration.
  • Food therapy - The goal of TCVM food therapy in treating gastroenteritis and colitis is to reduce inflammation and keep energy, or qi, flowing freely throughout the body. In Chinese medicine, the digestive system is ruled by the “Earth Element.” Imbalances in this element can lead to digestive disorders, vomiting and diarrhea (aka gastroenteritis). Foods that feed this element include:
    • green tripe and/or spleen
    • lamb, chicken, pumpkin, and sweet potato. If blood or mucus is present in diarrhea (“hot” diarrhea), a cooling diet is better. Examples of cooling (or neutral) foods include turkey, pork, rabbit, and fish, medicinal (Shiitake, Maitake, Reishi) mushrooms, dark leafy greens, and butternut squash.
    • Congee is an ancient rice porridge made by cooking rice in water for several hours until the rice particles fall apart. If tolerated, rabbit or pork along with grated ginger can be added.
  • Herbs - Herbs such as coptis, marshmallow root, plantain and golden seal can be used to resolve stagnation, eliminate dampness, and reduce inflammation. Garlic has antibacterial and antimicrobial abilities. Other herbs and fungi that support the digestive system include boswellia (frankincense), milk thistle, neem, and turmeric. There are several Chinese herbal blends beneficial for the treatment of diarrhea and resolving spleen qi and liver qi stagnation.
  • Probiotics – Probiotics support the microbiome of the gut and the immune system. Probiotics are essential if the cause of the condition is bacterial, and antibiotics are prescribed. S boulardii is a probiotic yeast that will survive antibiotics, manage diarrhea, and support the digestive process.  Adding digestive enzymes sooth and heal the gut and can help resolve diarrhea.
  • Medicinal mushrooms such as Reishi, and Lion’s Mane support the digestive system and have anti-bacterial, anti-fungal and anti-inflammatory properties.
  • Fiber supplementation – adding fibrous food like fruits and vegetables will slow down the digestion process and allow nutrients to enter the bloodstream. Supplemental fiber powders can also be added to food.

 The gastrointestinal system is very important in overall health.  Approximately 90% of a dog or cat’s immune system resides in the gut. Learn the signs and symptoms of gastrointestinal distress and act quickly to get your pet to your veterinarian if you observe them. Feeding a species-appropriate whole food diet rich in nutrients is essential in the prevention and treatment of gastroenteritis and colitis.  Maintaining balance through high-quality food, probiotics, herbs, and mushrooms can help to prevent these conditions from happening in the first place. 


Back to blog