Diarrhea in pets is not a disease, but a symptom that may have many causes. It is the passage of unformed stools. Most causes involve inflammation of one or more sections of the pet's gastrointestinal (GI) tract. Most cases have increased volume and frequency resulting from increased speed of passage through the GI tract. Diarrhea varies in severity from relatively mild cases, which usually respond to symptomatic treatment, to serious or life-threatening illnesses.
There are many causes of diarrhea. The most common cause of diarrhea in dogs is dietary indiscretion. Dogs are natural scavengers and tend to eat indigestible food substances that they find. Often their human companions may also share table scraps with them, which may not be tolerated well. Diarrhea from dietary indiscretion tends to be a milder condition, which usually responds well to symptomatic treatment. Some other minor causes of diarrhea may include gastrointestinal viruses, intestinal parasites, and even stress.
If your pet has acute diarrhea and doesn't appear systemically ill, first rest the gastrointestinal tract by withholding food for 12 – 24 hours. Leave water accessible at all times. If your pet responds favorably in the first 24 hours, start on an easily digestible, low fat diet. For example, rice with boiled skinless/boneless chicken or rice with ground beef. Feed small meals 3-4 times daily for 2 days. Once stools are normal, gradually switch back to your pet's regular diet.
Sometimes even mild cases can become more serious because of dehydration. Please contact us if your pet:
- Has diarrhea for more than 24 hours
- Has bloody diarrhea or stool is black and tarry
- Also has vomiting
- Is weak, lethargic, or has a fever
It is important to provide a detailed medical history when you consult your veterinarian, such as:
- Your pet's vaccination history
- How long the problem has been going on
- Whether your pet has any other clinical signs
- If your pet has had table scraps or other dietary indiscretion
- Consistency and frequency of stool
- What exposure your pet has had to other animals or environments
Your veterinarian may also want to perform diagnostic tests — such as a fecal examination, bloodwork, and/or abdominal radiographs — to determine the cause of your pet's diarrhea. In some cases, your vet may even offer referral to a specialist for endoscopic examination, GI biopsies, or abdominal ultrasound. Treatment may include antibiotics, GI motility medications, and special diets. If your pet isn't improving in 2-3 days with treatment, a change in medications or further diagnostics may be needed.
Chronic diarrhea (present for more than 2-3 weeks) may be more difficult to diagnose and treat. Sometimes a definitive answer is not found even with extensive work-up. Many cases may require food trials along with medical management.
A similar diagnostic/treatment plan may be followed in cats. However, keep in mind that some human over-the-counter diarrhea medications may contain acetaminophen or ASA, which are dangerous for cats. Never use a medication without first consulting your veterinarian.