Pet Connection by Dr. Marty Becker, Kim Campbell Thornton and Mikkel Becker

Loose Ends

When dogs have bloody diarrhea, it can be difficult to determine the cause -- here’s what to know

By Kim Campbell Thornton

Andrews McMeel Syndication

Diarrhea. It’s bad enough when a pet has stinky loose stools, but when they’re mixed with bright red blood -- or a pet strains to defecate and produces blood only -- even the most sanguine pet owner becomes concerned.

Causes of bloody diarrhea can include small, harmless masses; major tumors; toxic substances; or simply emotional upset. Fortunately, it’s rarely an emergency unless the dog is losing enough blood to cause significant anemia or if the dog is bleeding out of the gastrointestinal tract because of a toxin such as rat poison or a systemic disease, says Craig B. Webb, DVM, professor of small animal medicine at Colorado State University’s Veterinary Teaching Hospital in Fort Collins.

Sometimes the cause is never clear. That has been the case with my dog Keeper, whose digestive system is sensitive, to say the least. Usually his veterinarian prescribes antibiotics and a few days of a bland diet. But recent studies show that in some cases, symptomatic treatment -- a bland diet to soothe the digestive tract -- is all that’s needed.

Approximately 50% to 60% of dogs with acute onset of bloody diarrhea have fecal samples that are positive for a toxin called netF, produced by Clostridium perfringens bacteria. While many healthy dogs have C. perfringens as a normal part of their gut microbiome, in dogs with bloody diarrhea, C. perfringens bacteria are producing the netF toxin gene. The trigger may be something the dog has eaten, infection from another organism or some other cause.

“What makes a strong case that it might be causative is that only dogs with hemorrhagic diarrhea are positive for this toxin,” says Texas A&M researcher Jan S. Suchodolski, DVM, Ph.D., one of the authors of a study on the association of C. perfringens and netF toxin genes with acute hemorrhagic diarrhea published last November in the Journal of Veterinary Internal Medicine. “We don’t typically see it in dogs with acute non-hemorrhagic diarrhea or with chronic diarrhea.”

Dogs who are positive for the toxin, which can be identified through a molecular test, usually eliminate it quickly, independent of treatment with antibiotics, Dr. Suchodolski says.

Why no antibiotics?

They can have a significant effect on intestinal microbiota -- the “good bugs” that populate the intestine and play an important role in physiology, metabolism, nutrition and immune function. Broad-spectrum antibiotics disrupt the gut’s microbiome, killing beneficial bacteria.

“We’re discovering more and more that these effects are long-lasting,” Dr. Suchodolski says. “And dogs don’t recover quicker compared to not getting antibiotics for acute diarrhea.”

That doesn’t mean you don’t need to be concerned if your dog is pooping out blood. Small dogs with what is now called acute hemorrhagic diarrhea syndrome (AHDS) -- formerly known as hemorrhagic gastroenteritis -- can quickly become dehydrated, especially if diarrhea is accompanied by vomiting. A small fraction of dogs may go into shock or sepsis from dehydration and infection, and this may require hospitalization or antibiotics.

Signs that your dog should see the veterinarian as soon as possible include vomiting, lack of appetite, dehydration, increased heart rate and respiration and collapse.

If your dog has bloody diarrhea but is otherwise normal and alert, withhold food for 12 to 24 hours and then feed a bland diet for a few days. Ensuring that the dog is drinking water is more critical than getting him to eat, Dr. Webb says.

“At some point, probiotic therapy should be considered, as changing the gut microbiota may help long term,” says Joseph W. Bartges, DVM, professor of internal medicine and nutrition at the University of Georgia’s College of Veterinary Medicine.

Don’t hesitate to call your veterinarian if you’re worried. “If there are any concerns, especially if your pet feels bad and is not him- or herself, you should take them to a veterinarian,” Dr. Bartges says. “It is better to be safe than sorry.”


Cats need

daily play

Q: How much playtime do cats need daily?

A: More than you might think! Most of us think of cats as layabouts, happy to sleep all day; in reality, they are hunters who benefit from the opportunity to practice their inborn skills, even if they never catch a mouse in their life.

A good baseline is five minutes of playtime or interactive exercise twice a day. Kittens might need more, and senior cats might be happy with a little less. Toys and games your cat will enjoy include flashlight beams they can chase -- be sure to end by pointing the light at something they can pounce on so they’ll feel as if they accomplished something -- fishing pole-type toys with a dangly, preylike object at the end or small balls that your cat can chase down the hall, zigging and zagging as the ball bounces off walls or other objects.

Another way to keep your cat fit and occupied is to teach him to work for his meals. Not by catching mice -- although plenty of cats make a living doing that -- but with a puzzle toy that he must push or play with to get it to dispense food. I tell people that instead of leaving out a big bowl of kibble for their cat to snack from during the day, they should put a meal’s worth of food inside a treat ball and let him figure out how to get it out. Leave a couple of those balls around the house, and your cat will “hunt” when he’s hungry and get the amount of food he needs, not the amount he eats because he’s bored. This is also a good way to help overweight cats drop a pound or so.

You can find more about feline play at -- Dr. Marty Becker

Do you have a pet question? Send it to or visit


Need stress relief?

Pet a dog or cat

-- Petting dogs and cats relieves student stress, according to findings from a Washington State University study published last month in the open-access journal AERA Open. “Just 10 minutes can have a significant impact,” said Patricia Pendry, an associate professor in WSU’s department of human development. “Students in our study that interacted with cats and dogs had a significant reduction in cortisol, a major stress hormone.” Researchers divided 249 college students randomly into four groups. Salivary cortisol samples were collected from each participant throughout the day, starting in the morning when they woke up. Once data was analyzed from the various samples, results showed that students who interacted directly with the pets showed significantly less cortisol in their saliva after the interaction.

-- Salt lamps give off a pretty glow and are thought to have health benefits, but the large chunks of pink Himalayan salt can be toxic to pets who lick them excessively. Pets who ingest too much salt -- from licking a salt lamp, eating homemade play dough or getting into the rock salt for making homemade ice cream -- can develop salt poisoning. Signs include vomiting, diarrhea, appetite loss, lethargy, incoordination and excessive thirst or urination. Severe cases can result in tremors, seizures and death. Contact your veterinarian or a poison control hotline immediately if your dog or cat shows these signs. Keep salt lamps out of a pet’s reach, especially if you have a high-climbing cat or tall dog.

-- It’s hot out there! In times of extreme heat, keep pets indoors, where there’s air conditioning, or in a cool basement. Animals who go outdoors should have access to fresh water and shade all day. A child’s wading pool filled with cool water is also a good idea. -- Dr. Marty Becker, Kim Campbell Thornton and Mikkel Becker


Pet Connection is produced by a team of pet care experts headed by “The Dr. Oz Show” veterinarian Dr. Marty Becker, founder of the Fear Free organization and author of many best-selling pet care books, and award-winning journalist Kim Campbell Thornton. Joining them is behavior consultant and lead animal trainer for Fear Free Pets Mikkel Becker. Dr. Becker can be found at or on Twitter at DrMartyBecker. Kim Campbell Thornton is at and on Twitter at kkcthornton. Mikkel Becker is at and on Twitter at MikkelBecker.