If your dog has been having bouts of bloody diarrhea, it's important to determine the cause as soon as possible. While some causes may be benign and require no treatment, others can be serious and even life-threatening. Bloody diarrhea is an important sign that something is wrong with your dog. It's important to find out what is causing bloody diarrhea so you can help your dog get better.

This article will explore the 7 most common causes of bloody diarrhea in dogs, and why it is important for dog owners to be aware of them. Bloody diarrhea can be a sign that something is wrong with your dog, so it is important to determine what is causing it. By being aware of the common causes of bloody diarrhea in dogs, dog owners can help their dogs get better faster.

1. Intestinal parasites

Intestinal parasites are one of the most common causes of bloody diarrhea in dogs. These parasites can cause inflammation and irritation in the intestines, which can lead to bloody diarrhea. Intestinal parasites can be very serious and are important for dog owners to be aware of the symptoms of intestinal parasites so they can get their dogs treated as soon as possible.

Common intestinal parasites that can cause bloody diarrhea in dogs include:

Other symptoms that may be present if your dog has an intestinal parasite include weight loss, vomiting and abdominal pain.

Intestinal parasites are treatable, but it is important to take your dog to the vet as soon as you notice any symptoms. If left untreated, intestinal parasites can cause ongoing health issues for your dog.

2. Infectious diseases

Infectious diseases are caused by microscopic organisms such as bacteria, viruses, fungi or parasites that can invade the body and multiply, causing serious illness.

Some of the most common infectious diseases include

These infectious diseases can cause bloody diarrhea in dogs, as well as vomiting, fever and lethargy.

Bacterial infections such as clostridial, campylobacter and E.Coli are treated with antibiotics whereas viral infections such as parvovirus and distemper are much more serious and often require hospitalization.

Infectious diseases are serious and can be life-threatening, so it is important to take your dog to your veterinarian as soon as you notice any symptoms. Early diagnosis and treatment are essential for the best chance of recovery.

3. Dietary indiscretion

Bloody diarrhea in dogs can be a sign of dietary indiscretion, which is when a dog eats something that disagrees with them. This occurs very commonly and can happen if they eat something that is spoiled or contaminated, or if they eat something they're not used to.

Signs of dietary indiscretion include vomiting, diarrhea, and decreased appetite. If you notice any of these signs in your dog, take them to your veterinarian right away. Dietary indiscretion can be serious, so it's important to get your dog checked out by your veterinarian as soon as possible.

4. Hemorrhagic Gastroenteritis (HGE)

Hemorrhagic Gastroenteritis (HGE) is characterized by the sudden onset of profuse, bloody diarrhea and vomiting, often with no apparent cause. Diarrhea that results from HGE typically has a distinctive, unusually bright or dark red colour, which can be quite alarming.

The exact cause of HGE remains unclear, but it is theorized that it could be related to bacterial infections, dietary changes, stress, or hyperactivity of the dog's immune response. While any breed or age of dog can be affected, it seems to occur more frequently in small and toy-breed dogs.

Rapid diagnosis and treatment are vital as HGE can lead to severe dehydration and shock, which can be life-threatening without prompt veterinary intervention. The condition often resolves quickly with appropriate treatment, but it can recur in some dogs. Therefore, any dog presenting with bloody diarrhea should be evaluated by a veterinarian immediately to rule out HGE and other serious conditions.

5. Ulcerative colitis

Ulcerative colitis commonly affects Boxers and French bulldogs, although it can occur in any breed. It is a condition that causes ulcers to form in the lining of the intestine, which can lead to bloody diarrhea in dogs. Other symptoms of ulcerative colitis include weight loss, lack of appetite, and abdominal pain. Ulcerative colitis is a serious condition that requires treatment from a veterinarian.

Recent research suggests that the main cause of ulcerative colitis in dogs is a particular strain of E.Coli that creates a severe abnormal immune reaction in the colon. Treatment includes a specific antibiotic protocol to treat ulcerative colitis in dogs.

6. Stress colitis

Stress is a common cause of bloody diarrhea in dogs. Stress can be caused by many different things, including changes in routine, travel, boarding, or even moving to a new home. When a dog is stressed, it can lead to a condition called stress colitis. Stress colitis is a condition that causes inflammation in the colon. This can lead to bloody diarrhea in dogs. Other symptoms of stress colitis include vomiting, weight loss, and abdominal pain. If you think your dog may have stress colitis, take them to your veterinarian. Stress colitis is a serious condition that requires treatment from a veterinarian.

7. Poisoning and toxins

Certain types of toxins can cause bloody diarrhea in dogs. Some examples include:

If you think your dog has ingested a toxin, take them to your veterinarian right away. Poisoning and toxins are serious conditions that require treatment from a veterinarian.

Dogs affected by toxins will often have a variety of other, concurrent serious symptoms in addition to bloody diarrhea. These may include vomiting, lethargy, tremors, and seizures. If you think your dog has been poisoned, call your veterinarian or the Pet Poison Helpline at (855) 764-7661 immediately.


In summary, 7 important causes of bloody diarrhea in dogs include parasites, infectious diseases, dietary indiscretion, HGE, ulcerative colitis, stress colitis, and toxins. If you're a dog owner, it's important to be aware of these causes of bloody diarrhea in dogs. All of the causes of bloody diarrhea in dogs that we've listed have one thing in common: they're all serious conditions that require treatment from a veterinarian. If your dog has bloody diarrhea, it's important to take them to your veterinarian right away so that it can get the help they need.