Why Does My Dog Have Diarrhea


why does my dog have diarrhea

I must admit I do panic a bit (okay more than a bit!) when I notice my dog has diarrhea.

Being a senior dog with quite a few health issues, keeping Red well is a balancing act, which, with the help of my trusted vets, we’re doing a great job of. I do my best to ensure nothing “throws her off” even though she’s an exceptionally strong dog in all meanings of the word.

Knowing that with diarrhea often comes dehydration, that’s really a big concern as dehydration can be deadly, especially in seniors.

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Causes of diarrhea in dogs

  • Eating something off the street
  • Getting into the garbage
  • Ingesting a toxin
  • Reaction to new supplement or medication
  • Too much oil such as fish or coconut
  • NSAIDs (non steroidal anti-inflammatories)
  • Sudden change in diet
  • Drinking standing water
  • Bacterial infection
  • Parasites
  • Gastrointestinal disease
  • Addison’s disease
  • Liver disease
  • Inflammatory bowel disease
  • Pancreatitis
  • Cancer
  • Kidney disease

call your vet if your dog has diarrhea

My dog has diarrhea – what do I do about it?

The first thing you DON’T do is give your dog some kind of over the counter medication someone told you is good for diarrhea in dogs.

I recommend you first check if he/she is dehydrated, because it only takes a second. That’s easily done by gently pinching some fur on the back of your dog’s neck, then releasing. If the skin goes back into place immediately, that’s a good sign. If it takes time that means your dog is dehydrated. The longer it takes, the more dehydrated he is.

Next call your vet and tell him (or her) what’s been going on, and whether or not your dog seems dehydrated. Don’t wait a day or two to see if the diarrhea clears up on its’ own before calling. Adopting a “wait and see” when it comes to something out of the ordinary with a senior dog, is never a good idea.

If you notice blood, you absolutely must tell your vet and get an appointment that day. Tell them you’ll happily sit in the waiting room until you can be squeezed in to see someone. Try and bring poop and urine samples if you can, as they can be analysed immediately.  


Your vet will ask questions such as:

  • When it started
  • If you noticed him eating anything off the ground
  • Did he get into the garbage
  • Has anyone been feeding him things he shouldn’t be eating
  • Have you changed his diet recently

Anything you can think of would help your vet figure out the reason.

Urine and poop samples can be analysed on the spot to give your vet some idea of what’s been going on. Sometimes they have to be sent off to a lab for further analysis in order to get a definitive diagnosis, but often testing at a vet’s office is enough to at least get your dog started on a treatment plan.


The treatment will depend on the cause, but in my experience your vet will give your dog some anti-diarrhea medication and anti-nausea if he’s been throwing up. You will likely take some home and administer over the course of a few days. If your dog seems at all dehydrated, he will be given IV fluids either for a few minutes or several hours, depending on the severity. Rehydration sachets added to drinking water may also be needed.

Your vet may also recommend a few days of a bland diet such as boiled chicken and rice.  A wormer will be given if they are detected.

Only your vet can provide you with a treatment plan once all test results are known.


Keeping your dog in optimal physical and yes even mental condition, can help him handle upsets more easily than a dog in poor condition.

Give him plenty of physical exercise (the type and duration depending on physical abilities), mental stimulation, a nutritious diet, supplements and regular vet checks are a great start.

Take care when your dog is running off leash to make sure he doesn’t get into garbage, which I know can be challenging. Teaching him “leave it” or “drop it” will go a long way in that if you do catch him with something in his mouth, learning those commands means there’s a good chance he’ll let it go before he gets a chance to gobble it up.

Ask your vet for a probiotic or other supplements to support his digestive system.

If you are changing over his diet, do it very gradually over the course of at least a week, especially if he seems sensitive to changes.

Do not add supplements or change doses without consulting your vet.

Keep poisonous plants and other potential toxins out of reach.

Don’t let everyone be so “free handed” when it comes to giving your dog treats or table scraps.

Red rarely gets diarrhea anymore

Red and diarrhea

There was a period of time when Red would get bouts of diarrhea for various reasons, too often for my liking. Each time my vet would prescribe Metronidazole, and when she was dehydrated she would get IV fluids. I would keep some of the medication here so I could start her on it immediately, and not waste hours until I could get to the vet. I also keep Royal Canin Rehydration Support sachets on hand, to add to her drinking water to help replace electrolytes. My vet usually recommends it after having fluids just to help her along.

Red recently had a brief episode of vomiting and diarrhea, but that’s because she found something in the grass. I usually have eyes in the back of my head, but this time I didn’t turn around quickly enough when I realised she wasn’t walking with me. Some quick fluids and an anti-nausea medication and she was fine.

Other than that she hasn’t had diarrhea in several months, and I believe that is largely due to a change in her diet and regular acupuncture sessions. She now eats a home cooked, whole foods diet and the acupuncture has boosted her immune system.

Now that she is seeing a holistic vet, I am looking to move away from medications to more natural treatments whenever possible.

Why does my dog have diarrhea – conclusion

Whatever the cause diarrhea can be serious if left untreated, particularly when dehydration is present.

Any changes in behaviour, peeing and pooping or physical appearance no matter how slight, needs to be followed up with at least a phone call to your vet’s office. You know your dog better than anyone, and if you have a concern you have to make sure you are heard…and taken seriously.

A “wait and see” attitude is never wise when you are caring for a senior dog, especially one with health issues, so if your vet doesn’t take you seriously, find one who does.

What treatments have worked for your dog’s diarrhea? Sharing helps others so please leave your comment in the section below.



Why Does My Dog Have Diarrhea
Hindy Pearson
Helping people care for their senior dogs
I am a certified dog trainer and pet care consultant, specialising in working with rescue dogs and first time pet parents. I foster and adopt senior and special needs dogs, and advocate for shelter adoption of all animals, particularly older dogs and cats. I am currently working on a spay/neuter program in Spain.

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