GiarCidia Fen-Wormer – Fenbendazole Liquid Dewormer for Dogs and Cats

4 types of wormsFenbendazole 10%Made in the USA

Fen-Wormer

Fenbendazole 10% liquid dewormer · dogs and cats

$34.99 $44.99

Four common worms: tapeworm, roundworm, hookworm and whipworm.
Short course: once a day for 3 days.
Easy to give: a liquid with the dosing syringe in the box.

How much does my pet need? Work it out by weight

Purchase option Subscribe & Save 10%$31.49every orderKeep a bottle on hand for the next course.

10% off every order
Ships every month
Pause, skip or cancel anytime

One-time purchase$34.99

Secure checkout · Free shipping over $70

Treating something else too?

FleasDefender $39.99

6 types of wormsZap-Wormer $58.99

CoccidiaToltraBoss $42.99

What does it treat?

Tapeworm, roundworm, hookworm and whipworm, in dogs and cats.

How do I give it?

Shake well. Use the dose for your pet's weight from the label chart, by mouth or in food. Once a day for 3 days.

Fen-Wormer or Zap-Wormer?

Fen-Wormer covers 4 worms. Zap-Wormer covers 6, adding pinworm and lungworm.

Do I need a prescription?

No. It's sold over the counter, so you can treat at home.

Made in the USAFDA-approved facility
Dogs & catsOne formula for both
Syringe in the boxDose by weight

“We have used the dewormer for about 5 litters now. It works extremely well. I will be telling all of my breeder friends about it. Thanks Giarcidia.”

D&T Services

Treats 4 types of worms
Fenbendazole 10%
Once a day for 3 days
Syringe in the box
Dogs and cats
Made in the USA
5.0 on Google
Free shipping over $70

Everything in the bottle. Nothing to guess.

Fenbendazole 10%Oral suspension, dosed by weight
4 types of wormsTapeworm, roundworm, hookworm, whipworm

Syringe in the boxMarked to 3 ml; 5 lb = 1.2 ml
Made in the USAIn an FDA-approved facility

Good

It works really well just follow the directions

A+ WORKS! This medicine worked great!

This medicine worked great! My dogs didn’t have an issue with the flavor. I noticed them more playful and got back their appetite.

Effective and efficient

I am using nothing that is packaged in plastic as it’s toxic, I liked that this medicine comes in a glass bottle, well protected with bubble wrap! Both my dogs and cats took it well, my cats are very picky so I just mixed it in their food once they were very hungry and they ate it. 2 of my dogs expelled worms and 1 of my cats vomited worms! This medicine works !

Works like a charm!

The video showcases the product in use.The video guides you through product setup.The video compares multiple products.The video shows the product being unpacked.Video Player is loading.Click to play videoPlayMuteCurrent Time 0:00/Duration 0:08Loaded: 37.54%0:00Stream Type LIVESeek to live, currently behind liveLIVERemaining Time -0:08 1xPlayback RateChaptersChaptersDescriptionsdescriptions off, selectedCaptionsCaptions off, selectedEnglishAudio Trackdefault, selectedFullscreenThis is a modal window. Great medicine, my dogs took it well with or without their food. They are happy! I had a few dosage questions, reached out to the company and they answered my concerns. Highly recommended!

Worked Fast!

My dogs liked the taste and one of them did expelled worms. I can tell it worked both my dogs seemed happier and it seemed to have fixed their storage issues. I honestly recommend it.

5 stars: 6 (100%)
4 stars: 0 (0%)
3 stars: 0 (0%)
2 stars: 0 (0%)
1 star: 0 (0%)

Works like a charm!

Quality and effective dewormer!

This stuff is Amazing and works wonderful! My German Shepard Luke was unhappy, didn’t want to eat and was loosing weight. I gave him the proper dosage and within a few hours he pooped out worms! Like noodles !! He then started acting better, more playful and being back to himself. He also didn’t mind the taste!! It came nicely packaged and in a glass bottle not plastic. For Duke and I, this is the best dewormer!

Good

It works really well just follow the directions

A+ WORKS! This medicine worked great!

This medicine worked great! My dogs didn’t have an issue with the flavor. I noticed them more playful and got back their appetite.

Effective and efficient

Worked Fast!

My dogs liked the taste and one of them did expelled worms. I can tell it worked both my dogs seemed happier and it seemed to have fixed their storage issues. I honestly recommend it.

Measure. Give. Repeat.

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Step 1 Measure
5 lb = 1.2 ml, up to 40 lb = 9 ml.
Step 2 Give
By mouth, or mixed into food.
Step 33 days Repeat
Once a day for 3 days.

Follow the directions and cautions on your bottle's label.

How much to give, pet by pet.

Move the slider to your pet's weight. We'll show the daily dose, the full course, and which bottle covers it.

How many?

About how heavy, on average? 20 lb

Your 20 lb dog gets

4mlonce a day

Your dog needs about 40 ml for a full 3-day course.

1 × 120 ml covers it

From the Fen-Wormer label chart: 5 lb 1.2 ml, 10 lb 2.5 ml, 20 lb 4.5 ml, 30 lb 7 ml, 40 lb 9 ml (in between, we estimate from the rows either side; over 40 lb, combine doses). Once a day for 3 days.

Frank Bustos showing one of his Rottweilers

Started in a breeder's kennel.

GiarCidia Inc. was founded in February 2024 by a dedicated breeder who spent nearly a decade raising show-quality and family-oriented Rottweilers. Throughout those years, his top priority was ensuring that every puppy went home healthy, happy, and free from worms and parasites.

Like many breeders, he faced the ongoing challenges of Giardia, Coccidia, and intestinal worms, conditions that can seriously impact a puppy’s health and, in some cases, even result in loss of life. Determined to find a better solution, he made countless veterinary visits and explored various treatment options. Despite his efforts, he found no reliable protocol that consistently delivered the results he was looking for.

Rather than accepting the problem, he committed himself to finding a solution.

Read Frank's full storyShow less

After more than two years of extensive medicine research, conducting trials, evaluating results, and spending countless hours in the laboratory, Mr. Bustos developed a formula that consistently produced positive results within his own breeding program. Wanting to ensure its effectiveness beyond his own litters, he provided trial products to breeders across the United States, allowing them to test the formula with their own puppies before introducing it to the public.

The feedback was overwhelmingly positive.

Following that feedback from breeders, the formula was later expanded for use in cats as well. Throughout the development process, GiarCidia remained committed to quality and compliance, including making every product in an FDA-approved facility and following applicable FDA guidelines.

Today, our products are trusted by breeders and pet owners across the country. Our formulas are made to help treat common intestinal parasites, and we believe pet owners should have access to solutions that can be given conveniently from home, reducing unnecessary stress on both pets and their families.

Our products are manufactured with quality in mind and are available in a variety of natural flavors to make giving them easier and more enjoyable for your pets.

With customers across the USA and more than 100 five-star Google reviews, we are proud of the trust our customers place in us. Nothing is more rewarding than helping pet owners see their dogs and cats healthy, thriving, and living their best lives.

GiarCidia products were not created by someone looking to enter the pet health industry overnight. They were developed by someone who personally experienced the same challenges faced by breeders and pet owners every day. Through years of hands-on experience, research, testing, and dedication, Mr. Bustos developed solutions designed to address real-world problems and provide practical support for the health and well-being of pets everywhere.

10 yrs: Breeding Rottweilers
2+ yrs: Developing the formula
5.0: On Google, 136 reviews

Frank BustosFounder & CEO, GiarCidia

Fen-Wormer vs. tablets.

A liquid you give by mouth or in food. No pill to hide, nothing to split.

LiquidNo pill to hideDoseFor your pet's weightSyringe in the boxDogs & cats

GiarCidiaFEN-WORMERTo the ml

TabletsFixed sizes

Good to know.

Before you start

Shake well before use
Once a day for 3 days
Label chart: 5 lb 1.2 ml · 10 lb 2.5 ml · 20 lb 4.5 ml · 30 lb 7 ml · 40 lb 9 ml
Follow the label's directions and cautions
Keep out of reach of children

Questions, answered.

What does Fen-Wormer treat?

Four common worms in dogs and cats: tapeworm, roundworm, hookworm and whipworm.

How do I give it?

Shake well. Find your pet's weight on the label chart, draw up that dose with the syringe, and give it by mouth or in a little food. Once a day for 3 days.

Fen-Wormer or Zap-Wormer?

Fen-Wormer covers 4 worms. Zap-Wormer covers 6, adding pinworm and lungworm.

Do I need a prescription?

No. It's sold over the counter, so you can treat at home.