VETOQUINOL Enisyl-F Lysine Bites Chicken & Liver Flavored Immune Supplement for Cats, 6.35-oz bag -

Vetoquinol Enisyl-F Lysine Bites Chicken & Liver Flavored Immune Supplement for Cats, 6.35-oz bag

By Vetoquinol
Rated 3.6068 out of 5 stars
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$28.99Chewy Price
$27.54Autoship Price
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About This Item


  • Made in the USA.
  • Comes in a highly palatable poultry flavor, and may also be used as directed for as long as needed.
  • These small, bite-sized treats are specifically developed for cats and kittens to help treat conditions responsive to lysine such as upper respiratory problems.
  • They also work to reduce the severity and duration of symptoms caused by the feline herpes virus.
  • Routine administration of these treats can reduce herpes flare-ups as well as inflammation of the eyes, conjunctivitis, squinting, sneezing, sinus congestion and more.

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Nutritional Information

Feeding Instructions


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Trusted Immune System Support

Adding L-lysine as a supplement to your cat's diet is an easy way to help support her long-term health. As a market leader with a wide range of L-lysine products, Vetoquinol puts this active ingredient in tasty chews and bite-size morsels, plus paste, gel and powder form so you can find the best way to offer it to your kitty. These supplements are specifically designed for felines to support the immune system, and maintain respiratory an

Seal of Quality

Out of thousands of animal supplement companies, only a hundred are audited NASC members, including Vetoquinol. That means they've undergone a comprehensive quality audit to earn the NASC Quality Seal. Displaying this seal on their products means that you can rest assured that they are committed to following the highest current standards of quality in the industry.

Enisyl-F & Viralys Products

Specially formulated Enisyl-F was the first lysine-based nutritional supplement developed for veterinary use for kitties. Supplementing with L-lysine is helpful for managing the symptoms of upper respiratory infections in kittens and cats that were strays, and those in shelters.


Veterinarian formulated to deliver just the right dose in a treat with cheese, chicken, liver and hickory smoke flavors.


Tiny mouthfuls of L-lysine disguised as a delicious snack with savory chicken fat and chicken liver.

Oral Paste

Highly palatable paste that can be given by mouth, mixed with food, or even applied to paws for your cat to lick off.

Oral Powder

Delivers L-lysine HCl in a powder with fish and poultry liver flavors that cats crave—just sprinkle it on top of food.

Oral Gel

Cats only need a small amount of this extremely palatable gel to get the benefits of L-lysine HCl.

About Vetoquinol

Vetoquinol is a family-owned company devoted exclusively to finding innovative solutions for animal health issues. They've shown more than 80 years of dedication, researching everything from oral hygiene to urinary and kidney health to create products that are effective and safe for the pets you love and care about. Founded in 1933 with an expertise in pet pain management and veterinary resources, Vetoquinol has gained the continued trust of pet parents and vets worldwide.
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Questions & Answers

7 Customer Questions

How many chews are there per bag?
Answer by ChewyJan 24, 2018
As this bag is measured by weight, there is no approximate number per bag.

Can the bites and the powder be used together? We've begun feeding wet food only once a day for weight management and our herpes-positive cat is now only getting one dose of Lysine.
Answer by ChewyJun 12, 2018
Before combining any supplements, vitamins, or medications, it's always recommended to consult your vet for the healthiest and most accurate use.

I am looking for a crunchy lysine treat for my cat. I purchased soft chews and she refuses to eat it. are these crunchy?
Answer by ChewyOct 11, 2017
These treats are soft chews.

how big are the bites?
Answer by ChewyJan 09, 2019
The treats are approximately the size of a green pea.

ReviewsWrite a Review

Rated 3.6068 out of 5 stars
323 Ratings
Would recommend to a friend

323 Customer Reviews

Rated 5 out of 5 stars
By LP on May 30, 2023


My cat was diagnosed with FHV and my vet recommended these treats whey he has a flare up and the fact that I can get them on Chewy with no prescription is perfect! They usually help clear him up in a handful of days and if I constantly give them to him daily, he has zero symptoms at all times. Great produce, really does work!

Rated 4 out of 5 stars
By CatMom on Apr 24, 2023

Lysine for cats

We rescued 2 kittens, one who had a “drippy” eye. The Vet recommended these Lysine treats and both loved them. We only purchase when her symptoms are active because of the price. And we pare down the amount that we give. They prefer these over other treats and they do seem to improve her symptoms. Just too pricey! They are quite hard but not an issue with these kitties!

Rated 3 out of 5 stars
By Hardie on Apr 25, 2023

Outdoor cat will not eat Enisyl-F Bites at all

Outdoor cat will eat wet food with the powdered Lysine mixed in. But he eats around the Bites after tasting just one. Other cats will eat all the dry including the Bites. I can't recommend this product because the cat that really needs it refuses to eat it. And the other cats who do not need the Bites chow down on them. The outdoor cat will eat wet food with the powdered lysine mixed in.

Rated 5 out of 5 stars
By Ka on May 9, 2023

Does the trick

My granddaughter found this on your site and we tried it out ....have 2 very picky cats on eating and they hated taking Enisyl-F Lysine by the tube or spray but with some work I can get them to eat these...and it has helped both cats.

Rated 1 out of 5 stars
By Timmy on Feb 21, 2023


There isn't a low enough rating available! I bought these for my cat Timmy. Opened the bag and was a bit surprised at the shape/size of the treat. Had I only listened to my instinct. Timmy took the treat and choked on it. Despite my efforts at heimlich and then mouth to nose my beautiful, sweet little boy died in my arms.

Rated 5 out of 5 stars
By Cynd on Apr 18, 2023

Nice bite!

These chicken bites are great! They blend right in with the Cat Chow. Same size bite. She didn't like the gel with maple flavor at all. Chicken bites are best!

Rated 1 out of 5 stars
By yippee77 on Jan 16, 2023

None of my cats will eat this

My vet recommended lysine to help my older kitten that keeps having sneezing issues from the cat herpes virus. They sent me home with a paste that didn’t appeal to my kitten so I thought I’d try these treats. I also tried this for my other cats that have squinty eye issues. The treats are very hard, almost as hard as kibble. I don’t have picky eaters, but not a single one of my 4 cats would touch this. The kitten may get a pass because for some bizarre reason he doesn’t understand the concept of treats and won’t eat treats, but even the “eat anything and everything” cats wouldn’t eat this. I’m disappointed because these are pretty expensive. I did also buy the powder form and at least it’s going much better.

Rated 1 out of 5 stars
By Cindy on Dec 29, 2022

Description is wrong, consider before buying

I rated this 1 Star which is unfair since I don't know if the product works since my cats are not interested in this at all. Not sure if it's the smell or because it's hard as a rock. I even tried rolling it around in catnip! This are sold as being a soft chew which is not the case! They're hard as a rock, harder than crunchy food. I called the manufacturer and was told that they're supposed to be hard. Consider this before you purchase or if you have it and your cat isn't eating it, ask for a refund since it is not cheap. The manufacturer told me to try the powder version to add to their food. Hope this helps.

Rated 1 out of 5 stars
By catlover on Feb 3, 2023

It's way too HARD for cat's teeth!

I ordered this item for my senior cat because the description says "soft chew" but it's NOT ! I couldn't even break it myself :( Chewy sent me an replacement but it's same product. they should correct description " HARD" instead of "Soft chew" don't buy this product.

Rated 2 out of 5 stars
By Msmeg on Feb 3, 2023

hard, not cat approved

Our vet recommended this for feline herpes, but our furry boy refused to eat them. They're hard as rocks! I gave it to my sister for her cats and 1 out of 3 ate it, so it didnt go to waste, but 1/4 of the cats liking it isn't a great recommendation.