side effects of probiotics in dogs

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Dog probiotics are safe and good for their health. The side effects of probiotics in dogs are rare but should be carefully examined. These side effects are normally experienced by your dog when starting on probiotics.

Canine probiotics are used to balance the dog’s gut microbiome. They are also used to treat dogs with digestion issues. 

Side effects of probiotics in dogs

Side effects are normal and can be expected in the case where the bad bacteria are overwhelming the gastrointestinal (GI) tract.

The following are some of the side effects of probiotics in dogs:

  • Allergic reactions 
  • Diarrhea
  • Vomiting 
  • Change in appetite 
  • Constipation 
  • Gas
  • Effects from other ingredients

We will look at each side effect in detail below and highlight how they arise.

If you notice continual resistance by your dog’s body to specific probiotics, then you need to stop the dosage immediately. Speak to your vet about the situation and let the dog get examined for any underlying condition.

Do Dog Probiotics Cause Side Effects?

Dog probiotics are active supplements that are meant to change the gut flora of your dog. They are therefore capable of causing effects as they work.

Your dog can experience some side effects at various levels starting from the cellular.

You should always give your dog healthy probiotics only. The supplements should contain the bacteria that are naturally found in your dog’s GI tract.

Avoid products that have fillers, maltodextrin, and artificial sweeteners.

You can also give your dog homemade foods that contain probiotics.

Quality is Key

Low-quality probiotics may not work as intended and can cause severe side effects. Such products have very little or no live bacteria at the time of consumption.

Others are made with bacteria that are not found naturally in your dog’s gut. Your dog can become exposed to digestion issues when they take probiotics with foreign bacteria.

A high-quality probiotic will show the types of bacteria species and strains contained. You can either go for the probiotic with a mix of different species or the ones with a single species.

This will depend on what you want to achieve following your vet’s advice.

Superior probiotics will also indicate the number of bacteria that would be alive by the time of expiry. This will give you a good estimate of what to expect when buying the product. 

Always read the packaging labels of commercial dog probiotics to get all the relevant information.

7 Possible Side Effects of Probiotics in Dogs

Dog probiotics are considered to be safe and have very few side effects. The side effects listed below will rarely occur. If they do, they usually have mild effects on your dog’s overall health.

1. Allergic reactions

Researchers have found out that one in a million dogs who take probiotics would develop some allergic reactions. You can therefore see that this is a rare occurrence.

Some of the allergic reactions include itching, swelling, and difficulty in breathing. The exact cause of these allergic reactions is still unknown. 

Dog on grass

Some experts have stated that they arise from the effects of the bad bacteria trying to counter the incoming good bacteria.

2. Diarrhea

A new probiotic in your dog’s gut might upset their stomach. This is especially true for dogs taking probiotics for the first time. 

Can probiotics give my dog diarrhea? An upset stomach can cause digestive discomfort. This will alter the quality of their stool and eventually cause diarrhea. 

But it doesn’t affect all dogs, it will depend on how your dog reacts to them.

3. Vomiting

When your dog takes probiotics for the first time, he might vomit. This can be due to dietary intolerance arising from new bacteria.

Vomiting can also be a sign of severe health problems in dogs. Be sure to visit the vet if your dog vomits persistently.

4. Changes in appetite

Your dog might have some changes in appetite when getting started with probiotics. In most cases, they might lose their appetite because of the new gut flora.

toped dog food

Give your dog enough drinking water to stimulate their digestion and appetite.

5. Constipation

Your dog may have inconsistent bathroom breaks as a side effect of taking probiotics for the first time. 

6. Gas

New bacteria in your dog’s gut may cause a temporary increase in gas and bloating. This could occur if the dog has experienced flatulence before. This condition might increase first before decreasing and finally recovering.

7. Effects from other ingredients

The main ingredient of a probiotic is the bacteria species and strains. Artificial ingredients are sometimes used in the formulation of these probiotics. 

These might cause your dog to suffer some undesirable conditions. Some artificial ingredients may even put your dog at risk of getting infections.

A stressed dog

Always ensure that your dog gets a natural supplement, free from artificial ingredients. Amines from probiotics may cause your dog to have a mild headache during the first dose.

Always observe how your dog reacts after administering a probiotic. Your dog should be okay within a few days of taking probiotics. If the side effects become persistent, you need to seek your vet’s advice.

The Benefits of Probiotics Outweigh the Side Effects

The side effects of dog probiotics are nearly negligible. Giving your dog probiotics will yield far more benefits than side effects (if any). The advantages of these supplements are long-lasting and make your dog stay healthy.

Dog with treats

The side effects are rarely seen and, in most cases, do not affect your dog’s overall health. These side effects are mild and can only be seen within the first day of putting your dog on probiotics.

Once the probiotics are fully set in your dog’s GI tract, the microbiome will be restored and these issues will be lessened.

The Best Probiotic Dosage and CFU For Dogs

A good quality probiotic for your dog should have a daily serving of Colony Forming Units (CFU) of between 1 to 10 billion. This shows the number of bacteria that are available in the supplement.

The administration and dosage of probiotics will differ depending on several factors. These factors are; the form of the product, CFU per serving, and the size of your dog. You will need the following recommended dosage in most cases.

For chews:

  • 1 chew per day for dogs weighing up to 24 pounds
  • 2 chews per day for dogs between 25 to 74 pounds
  • 3 chews daily for dogs weighing 75 pounds and more.

For liquid probiotics:

  • 0.5 ml daily for dogs weighing up to 54 pounds.
  • 1.0 ml daily for dogs weighing 55 pounds and more.
Liquid probiotics for dogs

The dosage is different due to the number of probiotics per serving. You should follow your vet’s advice and manufacturer’s guidelines before giving your dog a new supplement.

For food-based probiotics, such as yogurt, it is best to get plain ones. Avoid sweetened yogurts as they may subject your dog to other health issues.

Review all the ingredients in any commercial dog product before purchasing.

Once you put your dog on probiotic supplements, you need to observe how he behaves. Take a close look at his daily behavior, overall health, eating, and sleeping patterns.

If you do not notice any improvements from his previous conditions, then you can adjust their dosage.

You should administer the probiotics to your dog during mealtimes to get the most out of it.

Can A Dog Overdose on A Probiotic?

It is nearly impossible to overdose your dog on probiotics. If you give your furry friend an excess dose, their body will only use what they need and excrete the rest.

Excess probiotics might cause your dog to show some side effects like flatulence, bloating, and sometimes diarrhea. You should not worry if you overdosed your dog with healthy probiotics. 

It is recommended to give your dog the right dosage every time. Remember that excess probiotic goes to waste and does not help your dog in any way.

The Final Word

The common side effects of probiotics in dogs are very rare to occur. This should not stop you from supplementing your dog’s diet with good probiotics.

Written By

Laura is the founder of Furs'n'Paws. She is a also a pet writer and expert with more than 20 years of experience of working with dogs and cats. She developed a very strong love for animals at a young age. Her passion led her to establish a thriving pet sitting and dog walking business in Dubai. As an expert in pet training, behavior, and nutrition, Laura is committed to helping pet owners and pet lovers by offering high-quality information on a wide range of topics.

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28 Responses

  1. My aged female dog started on probiotics to solve some gastrointestinal issues. The probiotic quieted down the issues but resulted in increased urination and incontinence. She has been on Proin to control the incontinence but it seems to be less effective.

    • Hi Stephen, I am not a certified vet but here’s a general idea of what might be happening. While probiotics are generally beneficial for gut health, some dogs may react differently, the increased urination might be a response to the changes in the gut flora. It’s good that the gastrointestinal issues have improved, but the side effect on urination needs attention. Proin is a medication commonly used to treat urinary incontinence in dogs however, its effectiveness can vary between individuals, and sometimes adjustments to the dosage or a change in medication might be necessary. Given the complexity of your dog’s situation, it’s essential to consult with your vet, they can evaluate the overall health of your dog, consider the history, and make adjustments to the treatment plan. Hope your dog gets well soon!

  2. Hi, I was recommended probiotics by my vet 17/04/23 as shes had diarrhea as sinse 14/02/23. so today 18th i will be going into her second days with. Its been 2hrs then 5 hrs after feeding shes vomitted she has not otherwise. she was at the vets 12th april as she was really lethargic so she was checked her hearts good and her temprature was fine. shes under weight. its getting the balance right and feeding her correctly i guess. she’s a staffie nearly 11.
    I will keep her pro biotics says only use for 3 days. taking each day as it comes bloods will be my next step middle the week if she dont improve.

  3. My 90 pound lab pointer mix, just ate the entire months supply of his probiotics. Just double-checking if anyone has some insight into what may happen. I think he’ll use what his body needs and the rest is wasted….. but he’ll be ok. Thanks for responding if you can.

    • Hi Lang, probiotics are not toxic, your dog might get diarrhea from eating the whole month’s supply. Just monitor him for a day or 2 for any unusual symptoms.

    • My dog had to be on antibiotics for thin poop,my vet suggested using VetriSciencePro Line Entero Flora Pro. This has worked for her so far, she will be 13 in September. Love this product.

  4. My yorkie poo has been on probiotics for a month and half does it change their behavior I noticed he sleeps more his poop looks fine can you let me know he is 9 years old

      • I ran out of my dogs probiotic. While i was waiting for my order she was off of the probiotic for 3 days. She had a horrible reaction to not having the probiotic in her system. She had terrible bloody diarrhea for days. I have been afraid to put her back on it. Is this normal for my dog to have bloody diarrhea when stopping the probiotic?

    • Funny that it is stated reactions are rare as I have two pug puppies who both get severe hives and vomiting from any probiotic. They are highly allergic to every strain

      • Sorry that your pugs had to go through this 🙁 Most dogs can have supplementary probiotics without any issues.
        Please speak to your vet for advice.

  5. We started our small poodle on probiotics because she kept scratching and anal gland issues but after 3 weeks her itching has got worse and now has black big freckles, white heads and a rash on her stomach, and no she doesn’t have flees but you would think she has.

      • Hi I started my dog on probiotics because he has diarrhea, I didn’t know that it was only 1 packet per day so I was giving him 2 and for about the first 2 days it was working but he’s back to having diarrhea again, what should I do?

          • Hi, my 11 month old dog just started having probiotic for a week now. The only side effects we noticed was diarrhea and constipation. Is it normal or should i stop?

          • Hi Fiel, giving probiotics may cause digestive symptoms such as constipation but will eventually subside after a few weeks of continued use. However, if your dog continues to have diarrhea several times a day it is best to take your dog to the vet.

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