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Diarrhea in Dogs

When a dog eats something they shouldn't, has a parasitic infection or is experiencing a medical condition, it can lead to gastrointestinal upset. Here, our vets in Nashua share the causes of diarrhea in dogs, how serious it is, what to do if you see blood and when it is an emergency.

Why do dogs get diarrhea?

Mild bouts of diarrhea are very common in dogs and can be caused by mild intestinal distress. Often, intestinal distress is directly tied to food, whether it be an adverse reaction to your dog eating a small amount of something that doesn't agree with them, such as table scraps, or switching to a new brand of dog food that isn't right for them.

There are various reasons for diarrhea in dogs, some of which can be serious and require immediate veterinary care.

Causes of Diarrhea in Dogs

Below are some of the most common reasons for diarrhea in dogs:

  • Stress or anxiety
  • Change in diet or treats
  • Eating garbage or spoiled food
  • Ingestion of foreign objects such as toys, bones, and fabric
  • Ingesting toxins or poisons
  • Viral infections such as parvovirus, distemper or coronavirus
  • Parasites - roundworms, hookworms, whipworms, Coccidia, or Giardia
  • Bacterial infections such as salmonella
  • Pancreatitis
  • Inflammatory bowel disease
  • Colitis - inflammation of the large intestine
  • Liver or kidney disease
  • Intestinal cancer
  • Medications such as antibiotics

What is the difference between acute and chronic diarrhea in dogs?

Acute diarrhea usually occurs suddenly and lasts less than two weeks. It is usually related to ingesting a substance or a change in diet. Chronic diarrhea in dogs is long-term, lasting more than two weeks. This type of diarrhea is usually associated with a medical condition that requires veterinary care.

How serious is diarrhea in dogs?

Recurring bouts of diarrhea over a short period could be a sign of a very serious health issue, particularly if your dog is very old, very young, or has a compromised immune system. Infections such as parvovirus are extremely serious, contagious, and life-threatening.

Is bloody diarrhea in dogs an emergency?

You should bring your dog to a vet as soon as you spot blood in their stool. That said, there are two types of bloody stools to look out for when your dog is experiencing diarrhea: hematochezia and melena.

Hematochezia: Results from bleeding in the lower digestive tract or colon. It is bright red and indicates certain potential medical complications.

Melena: Blood that has been digested or swallowed. This dark, sticky, almost jelly-like blood indicates that a severe problem in your dog's upper digestive tract might be to blame.

Occasional signs of blood may not have a serious cause. However, if bleeding is consistently present or in more significant amounts, it can indicate a medical issue or internal condition, such as a viral or bacterial infection, parvovirus, hemorrhagic gastroenteritis, or cancer.

No matter the amount or appearance of the blood, it is always best to contact your primary vet or nearest emergency vet right away. Describe precisely what you have observed, and your vet will give you detailed instructions on what you should be watching for and whether it makes sense for your dog to come in for a visit based on its symptoms.

When should I bring my dog to the vet?

For dogs who experience a single episode of diarrhea and are otherwise acting normal, there is likely no cause for concern. Monitor your dog's bowel movements to see if things clear up. However, more than two episodes could indicate a problem, so it's a good idea to call your vet if your canine companion has two or more bouts of diarrhea or if blood is in the stool.

If your dog is straining to pass a stool but only passing small amounts of watery diarrhea, they could be experiencing a painful blockage due to ingesting a foreign object such as a toy. This is a serious concern and needs veterinary attention right away. Contact your vet or head to the nearest emergency animal hospital for care.

Dogs showing other symptoms, as well as diarrhea, should also be seen by a vet as soon as possible. If your dog has any of the following symptoms, contact your vet right away to make an appointment:

  • Blood in stool
  • Unusual drooling
  • Vomiting
  • Lack of Appetite
  • Weakness
  • Signs of dehydration (Sunken, dry-looking eyes, dry nose, or dry, sticky gums)

If your dog displays any symptoms that cause you concern, contact your veterinarian. Your vet will let you know whether your pet's symptoms indicate that an examination is necessary.

What can I give my dog to treat their diarrhea?

Never give your dog human medications without consulting your veterinarian. Many over-the-counter medications that work well for people can be toxic to dogs.

If your dog has had one or two runny or soft stools, you may want to give your dog some time to recover by fasting for 12 - 24 hours.

A bland diet for a day or two may help resolve your dog's issue. Plain-cooked white rice with a bit of chicken and some canned plain pumpkin (not pie filling) may help make your dog's tummy feel better. Once your dog feels better, gradually reintroduce regular food.

Other things that might help to soothe your dog's upset tummy include natural yogurt, probiotics, peeled, boiled potatoes, cottage cheese, eggs with no oil added, specially formulated dog foods, and medications prescribed by your vet.

Regarding your dog's health, it is usually best to err on the side of caution. By taking your dog in for an examination, you allow your vet to determine the underlying cause of your dog's diarrhea and recommend the most effective treatment.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

If your dog is experiencing excessive or ongoing bouts of diarrhea, contact our Nashua vets immediately. We can help get to the bottom of your pet's gastrointestinal issues.

Welcoming Referrals and Emergency Walk-Ins

Animal Medical Center of New England welcomes emergency walk-ins and appointments when your pet needs us most. Our team of specialists is also accepting referrals from primary care veterinarians - fill out a referral form to get started.


Contact (603) 821-7222