We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

How Effective Is Brewer's Yeast for Fleas?

By Thomma Grindstaff
Updated Jun 04, 2024
Our promise to you
All Things Nature is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All Things Nature, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Brewer's yeast for fleas is thought to be effective, because the yeast contains thiamine. The smell and taste of thiamine is believed to be repulsive to fleas, so when dogs and cats eat brewer's yeast, the fleas are repelled by the presence of thiamine on the skin or in the blood of dogs and cats. Thiamine is a part of the B vitamin group.

Getting rid of fleas with brewer's yeast is easy to do, since the yeast is readily available from grocery stores, health food stores and online sources. It can be bought as a powder, a liquid or flakes. The most practical choice when it comes to using brewer's yeast is its powder form. For natural flea control, the powder can be mixed with pet food, dusted onto a pet's coat or dissolved in water.

Brewer's yeast for fleas should be dosed at 1 teaspoon (4.9 ml) for small dogs or for cats. Medium-sized dogs should be given 2 teaspoons (10 ml), and larger dogs should be given 1 tablespoon (14.8 ml). The yeast can be sprinkled on dog or cat food, or it can be used directly on pets' coats as flea-control powder. If Brewer's yeast is utilized as a dietary supplement, it can take up to a month before it reaches maximum flea control power. Pet owners might want to start dusting their pet's coat or supplementing their pet's diet with brewer's yeast early in the spring, before a major flea problem occurs.

A mix of brewer's yeast with garlic should be avoided. Garlic is toxic to both dogs and cats, with cats being more sensitive to garlic than dogs are. It is possible for either cats or dogs to be allergic to brewer's yeast. If a dog or cat shows signs of an allergic reaction on its skin after it eats brewer's yeast for fleas, then use of the yeast should be stopped. Dog and cat owners need to be careful about how much yeast they give their pets, since overdosing with Brewer's yeast can cause skin allergy.

Another way to use brewer's yeast for fleas is to allow 0.25 cup (59 ml) of the yeast to dissolve in 1 quart (946 ml) water. This solution can be put into a spray bottle and sprayed onto a pet's coat. For maximum effectiveness, the mixture should be combed or rubbed into the fur.

How To Use Brewers Yeast for Fleas

Powdered brewer's yeast is the easiest form to give your dog or cat. Entice your pet into taking the yeast by mixing it with wet food. You can make it look like gravy by dissolving the powder into hot water and then pouring the liquid over your pet's food. Or make it yummier by stirring the yeast into chicken or beef stock. Your pet will lap it up in no time.

If your pet doesn't seem to care for the smell of brewer's yeast, make a soup by boiling it in water to tone down the smell. Allow the liquid to cool and serve it to your pet within an hour so no nutrients are lost. Make a fresh batch daily.

What If Your Pet Won't Eat Brewers Yeast?

If your pet refuses to eat a yeast mixture, you can add the powder directly to your pet's coat. Start by removing the fleas with a flea comb and dipping the insects into soapy water to kill them. Put the yeast into a container with a sprinkle cap, spread it over your animal's coat and rub it in. Be sure not to exceed the recommended dose.

If your pet licks the powder off, don't worry. It's one way to get him or her to eat brewer's yeast! But be careful not to add too much, as it could give your fur friend an upset stomach or gas.

Can You Get Brewers Yeast in a Pill Form?

You sure can. The nice thing about purchasing brewer's yeast in tablet form is you can wrap it in a piece of deli meat and offer it as a daily treat. Most pets will gobble it up.

As long as your pet isn't older or susceptible to yeast infections, you can also purchase flea repellent pills that contain brewer's yeast from your local pet store. Read all the ingredients and follow the package instructions carefully to ensure you are giving your pet the correct dosage.

Can You Substitute Regular Yeast for Brewers Yeast for Fleas?

You can substitute regular yeast for brewer's yeast, but it's important to pay attention to the nutritional capacities of each. There are three kinds of yeast:

  • Brewers yeast. A strain of the fungi Saccharomyces cerevisiae, brewer's yeast is a byproduct of the beer-making process. Because it's dried at high temperatures, the yeast is dead. Although brewer's yeast has a bitter taste, it is loaded with powerful nutrients and can help with chronic disease.
  • Nutritional yeast. Grown from sugar or sugar beets, this yeast is specifically made as a nutritional supplement and can provide extra protein — just make sure you purchase the non-GMO kind. Like brewer's yeast, this is dried at high temperatures, and the yeast is killed in the process. Unlike brewer's yeast, nutritional yeast tastes better, with a nutty, cheesy taste. If your pet is a picky eater, nutritional yeast may be a better choice.
  • Baker's yeast. As a live yeast dried at much lower temperatures, this type doesn't have the same nutrients as brewer's or nutritional yeast. Specifically, it doesn't have as much thiamine and therefore won't be as effective in keeping away the fleas.

Save the baker's version for making bread and use either brewer's or nutritional yeast to protect your pet from fleas.

How Much Brewers Yeast To Give Pets for Fleas

To give brewer's yeast to your pet safely, you will need a teaspoon for a small dog or cat of 10 pounds or less. Add a teaspoon for every extra 10 pounds your pet weighs, up to 3 teaspoons, which equals a tablespoon of brewer's or nutritional yeast.

All Things Nature is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By anon1005004 — On May 31, 2021

Dogs can have garlic. I had a dog live 19 years because of garlic and never once did our vet tell us that garlic is deadly for dogs

By anon979151 — On Nov 24, 2014

Brewer's Yeast works. It has been several years since I had to deal with fleas and I'd forgotten how well it works. I use the nutritional variety (health food store) and if I can't get the powder I use the tablets and grind them up.

After three doses of about a teaspoonful mixed with 3 tablespoons of wet cat food, the fleas didn't just jump off; I am finding a few dead ones in various stages where my cats were laying.

I also called the company that makes the fogger that I also used and the rep suggested a hand-held spray for the closets. I'd already purchased one for hard to reach areas (under the couch and tv stand, beds) and the deck (where it probably started).

Another help is borax mixed with table salt worked into any rugs and left for 48 hours; also check for the eggs and larvae the animals leave behind and combing them at least three times a day. I've learned the hard way that if you live next to the woods or feral animals that your own pets need a flea treatment at least once a month! Or at least comb them a few times a month.

On this page
All Things Nature, in your inbox

Our latest articles, guides, and more, delivered daily.

All Things Nature, in your inbox

Our latest articles, guides, and more, delivered daily.