Vetoquinol Enisyl-F Paste Immune Supplement for Cats, 100 mL

By Vetoquinol
Rated 4.2183 out of 5 stars
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$38.99Chewy Price
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About This Item

  • Convenient dial-a-dose syringe aids in precise dosing and easy administration
  • Highly palatable oral paste that is easily accepted by most cats
  • L-Lysine is an amino acid that has been shown to reduce the severity and duration of feline herpes virus infections
  • Manufactured according to Good Manufacturing Practices (GMP) standards
  • Helps manage the symptoms of feline herpes virus, including sneezing, watery eyes and nasal discharge
Play Video: Learn More About Vetoquinol From Our Team of Experts
Learn More About Vetoquinol From Our Team of Experts

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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Top IngredientsPurified Water, L-Lysine Hydrochloride, Sorbitol...Active: L-Lysine Hydrochloride: 250mg per 1.25 mL., Inactive: Citric Acid, Edetate Disodium...Dried Brewers Yeast (grain & soy free); Catnip (Leaf); Chicken Liver (hydrolysate); Fish Oil (Salmon); L-Lysine Mono HCl; Mixed Tocopherols or Natural Tocopherols (Natural Preservative); Quercetin Dihydrate; Rosemary Leaf Extract....Active Ingredients per 1 scoop (0.52 grams): L-Lysine Hydrochloride ..... 500 mg Inactive Ingredients: Brewer's Dried Yeast, Hydrolyzed Fish (enzymatic), Hydrolyzed Poultry Liver (enzymatic)...Arabic Gum, Brewers Yeast, Calcium Propionate...
LifestageAdult, Kitten, SeniorAdult, Kitten, SeniorAdult, Kitten, SeniorAdult, Kitten, SeniorAdult, Senior, Kitten
Health FeatureEye Care, Immune Support, Respiratory CareImmune Support, Respiratory Care, Eye CareImmune Support, Eye Care, Respiratory Care, Allergy ReliefImmune Support, Respiratory Care, Eye CareImmune Support, Respiratory Care, Eye Care
Food FlavorTunaChicken, TunaChicken, Liver, Poultry, Meat
Food FormSupplementSupplementPowderSupplementSupplement, Treats
Special DietNatural, No Corn No Wheat No Soy, Non-GMO

Questions & Answers

12 Customer Questions

Can this be given to a 3 month old kitten?
Answer by ChewyJun 08, 2021
Vetoquinol Enisyl-F Oral Paste is suitable for kittens. Give kittens 6 months of age and under one pump (1mL) twice daily. Give cats 6 months of age and older two pumps (2mL) twice daily. Administration may be adjusted as recommend by your veterinarian,

My kitty is on a novel protein diet because of allergies. I noticed one of the ingredients is tuna flavor. Is there actual tuna or tuna oil in it?
Answer by ChewyMar 16, 2021
There is fish oil in the paste but the tuna flavoring is just a flavoring with no protein. Due to your pets specific health concern, we recommend consulting your Veterinarian to see what would be the safest for your pets current treatment plan.

does the paste come with syringe to administer it into cat's mouth?
Answer by ChewyJan 03, 2019
This paste does not have a syringe. Each press of the pump delivers 1ml (1 g) of paste. It can be applied directly in the mouth, on the nose or on the paws where it can be licked off. Alternatively, you may mix and offer at meal time.

Do you stop using this once symptoms subside or should you continue to use as a sort of immunity boost?
Answer by ChewyApr 29, 2019
This supplement can be used as an immune system support, however it is always recommended that you ask your vet to see if your cat needs to continue on this formula.

ReviewsWrite a Review

Rated 4.2183 out of 5 stars
142 Reviews
Would recommend to a friend

142 Customer Reviews

Rated 5 out of 5 stars
By CarolLK on Jun 19, 2022

Longtime user

I've been using this product for years. I used to be able to get it in sets of 6, but now have to order them individually at a much higher price than before. One of my cats is prone to eye infections and this product prevents them.

Rated 4 out of 5 stars
By Dogs on Jul 11, 2022

Cat doesn’t like

It’s good for her but Sadly My cat truly doesn’t like the taste. I’m not sure why this review has to be longer or it can’t be posted but that’s really all I had to say.

Rated 5 out of 5 stars
By Loki on Mar 23, 2022

Loki the orange cat

My male cat has been sickly since I adopted him from humane society. This product makes a huge difference in his health and he knows it! Before I go to bed every night he comes up to me for his lysine! He needs it. Just wish it was not so pricey!

Rated 1 out of 5 stars
By jsittig on Nov 30, 2021

Smells like rancid oil.

I have 11 cats and none of them will eat it. Not even mixed in their canned food. I tried to put it on their fur so they'd have to lick it off, they did because they couldn't stand it to be on their fur... I only got away with that once, because now they run away when they smell the container being opened. This was an expensive failure. Yuck!

Rated 5 out of 5 stars
By Peachez on Dec 4, 2021

Great product

It helps with immune system and viruses and helps them to wana eat as well..its great for animals.. I've bought this for many years. We've given this to all our cats. We have 4. Thank you chewy I'll order again as soon as I get to the last bottle... Thanks from my babies,...................

Rated 5 out of 5 stars
By Goody on Sep 14, 2021

Great Tasting

Our Ocicat is prone to developing ocular herpes when he experiences stressful situations so our vet recommended keeping him on this immune system booster, which isn't difficult because Tigger thinks it's a treat. He comes running whenever we call him to get his “yummy” and since we've been giving it to him, he hasn’t had a recurrence of the infection.

Rated 5 out of 5 stars
By 1kewlglamma on Aug 13, 2021

My girl asks for this twice a day!

Kali was born during the Paradise Fire in California three years ago, and has nasal, sinus and respiratory issues. Her vet started her on this product when she was six months old, three months after I brought her home from a shelter. I have similar health concerns, so I make sure to vacuum regularly and keep dust levels down. I'm so grateful for this stuff. Kali breathes better, doesn't have goop in her eyes, and has only needed two nasal flush procedures. When the cost through the vet's office increased dramatically, I was relieved to find it on Chewy!

Rated 5 out of 5 stars
By Katpie on Jul 28, 2021

Keep It On Hand

I have used this for years for my cats and kittens. Runny eye? bring out the Enisyl-F! Works for sniffles, sneezing, runny eye and on some cats it works within a day or two. Has not worked for wheezing that I can tell. For those having difficulty administering it, just pump it on your finger and then wipe it on kitty's front paws to be licked off. Most of my cats come running if I even touch the can and they lick it it off my finger.

Rated 5 out of 5 stars
By baby on Aug 30, 2021

Flavor change

The flavor in this was changed and my four cats that ate the other flavor loved it but they will not touch the tuna flavor now. Wish they still had the other one that they liked.

Rated 5 out of 5 stars
By Kittytownabbey on May 24, 2021

Great for a small kitten who has the sniffles.

First of all, thank's Chewy for your speedy delivery! I bought this for my smallest kitten who got the "kitty flu." She eats this from a dropper. She doesn't have an appetite for the wet food, so I take a couple droppers full of the gravy and mix it with 1 pump of this. Heat some water in the microwave and warm the bottom of the mixture dish up so it all warms up and melts together. Just like the package says to do, she gets 1 pump twice daily. I know I will need to keep this up for a while to support her health but she's improving. The sniffles seem to be slowly drying up. Her eyes are much better than they were at the beginning. She gives it two paws up for taste. She's eating the dry food, but she needs this to support her health in place of the wet food she's not eating at this time.