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What Are the Pros and Cons of Brewer's Yeast for Fleas?

Brewer's yeast is touted for its natural flea-repelling properties, thanks to its high B-vitamin content. It's a non-toxic, nutritional supplement that can support your pet's overall health. However, its efficacy is debated, and some pets may have allergic reactions. Are the benefits worth considering for your furry friend's flea woes? Dive deeper to uncover the full spectrum of brewer's yeast's potential.
Alex Tree
Alex Tree

Having a pet consume more vitamins and possibly liking the yeast tablet are some pros of using brewer’s yeast for fleas. Brewer’s yeast tablets rarely contain just yeast; dozens of vitamins and herbs are sometimes included to benefit the pet’s coat or help with flea prevention. In addition, some pets love the taste of the tablets, so treating a pet for fleas is no longer a problem. Brewer’s yeast has some downsides, however, such as not being proven to repel fleas and the possibility of causing gas.

Brewer’s yeast for fleas often comes in a tablet form fortified with other vitamins. Even if the flea treatment is ineffective, the dog may benefit from the other vitamins it consumed. In addition, unlike most other flea prevention methods, brewer’s yeast is not known to cause a reaction in dogs. Therefore, dogs with allergies and sensitivities may benefit from using yeast instead of potentially harmful chemicals found in some flea medications.

Brewer's yeast.
Brewer's yeast.

Using brewer’s yeast for fleas can be less of a hassle because some dogs and cats like to eat brewer’s yeast tablets. They see them as a treat, unlike getting liquid applied directly to their skin. In addition, dogs can be trained to know that a treat follows brewer’s yeast, even if they do not like the yeast. Cats are a bit difficult to train, but not impossible.

A flea.
A flea.

Studies show that using brewer’s yeast for fleas is ineffective when given to dogs in tablet form. One study fed brewer’s yeast to 40 dogs and unleashed and observed unfed fleas on the dogs over the course of seven weeks. The researchers saw no indication that brewer’s yeast could repel fleas. It could be another ingredient in most brewer’s yeast tablets that repels fleas, or dog owners could be experiencing a placebo effect.

Some cats and dogs consider brewer's yeast tablets a treat, so are glad to take them.
Some cats and dogs consider brewer's yeast tablets a treat, so are glad to take them.

Bloat in dogs can be a fatal condition; in fact, it is estimated that up to 60 percent of dogs die from the condition, even with treatment. It is caused by an excessive amount of gas building up in the stomach. Some foods and habits can cause gas and increase a dog’s risk of developing bloat. In general, experts advise against giving brewer’s yeast to a dog who is already at risk of bloat. It is important to talk to a veterinarian about the dog’s diet and how else to avoid bloat, especially if one or more of the dog’s relatives have died of the condition.

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Discussion Comments


My cat loves the brewer's yeast tablets. They seem to help him. I have a solid white cat, so I can see lots of fleas on him when he gets infested. The yeast does seem to get rid of the fleas.

@Pippinwhite -- I did sprinkle some on my cat's fur. Seemed like the flea population decreased. He doesn't have a problem with the commercial flea meds, but I don't want to give them all the time if a natural solution will work, too. But of course, if your baby has a bad reaction to the meds, don't ever give them to him.


If I thought brewer's yeast tablets would really work for my cats' fleas, I'd give them in a heartbeat. My older cat has a bad reaction to flea bites. Unfortunately, he also has a bad reaction to most flea medicines. They make him feel really bad. He drools and one kind even gave him a seizure! It was really scary.

They're not very expensive, so I'm willing to try them. I also wonder if brushing the yeast through his fur -- rather like flea powder -- might also help. I'll try nearly anything at this point! He's pretty miserable.

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    • Brewer's yeast.
      By: Stephanie Frey
      Brewer's yeast.
    • A flea.
      By: Carolina K Smith MD
      A flea.
    • Some cats and dogs consider brewer's yeast tablets a treat, so are glad to take them.
      By: fantom_rd
      Some cats and dogs consider brewer's yeast tablets a treat, so are glad to take them.
    • Giving a dog the tablet form of brewer's yeast may be ineffective.
      By: absolutimages
      Giving a dog the tablet form of brewer's yeast may be ineffective.