Cat guardians

Improve your cat's health with Polyprenyl Immunostimulant™

Available worldwide*

You are here because you are looking for help and have questions. All of us at VetImmune® are here because of our fur children and we want to help.

Polyprenyl Immunostimulant™ and your cat.

Polyprenyl Immunostimulant™ is a unique veterinary biologic USDA-approved for the treatment of feline viral rhinotracheitis (FVR, FRV, FHV-1), a common and ubiquitous upper respiratory infection (URI). Also referred to as PI or PPI, Polyprenyl Immunostimulant™ was designed and developed specifically for cats. PI works by upregulating innate immunity and directing the cellular immune response.

Following research conducted by Dr. Al Legendre of the University of Tennessee-Kentucky, PI is often used by veterinarians to treat cats with FIP (Feline Infectious Peritonitis). It is available through veterinarians.

Polyprenyl Immunostimulant™ order process.

You can order Polyprenyl Immunostimulant ™ (PI) online from our VetImmune store. We offer a simplified process that allows you to place your order and have it shipped to your US address without delay and start treatment immediately. Visit our retail store for details. 

Your veterinarian needs to place the order for you. Please download our  Package Insert and our US order form for US patients or our international order form for non-US patients and take those to your veterinarian. 

Your veterinarian may not be familiar with Polyprenyl Immunostimulant™ but is welcome to register on our site and to e-mail or call us at 1-209-600-7070 with questions.  Please use our locator to find veterinarians in your area who have experience with PI. 

Your veterinarian is the best source of information regarding the diagnosis and treatment of your cat. We will work with your veterinarian and with you to improve the health of your cat. If you have questions, please drop us a note at
Please note: under federal law, we cannot accept returns.

To place an order, download, print and bring the following documents to your veterinarian:

1 – Order form
  US form for US-based orders.​
  International order form for non-US orders

International buyers, please note: Panda Plus, s.r.o. is the official distributor of Polyprenyl Immunostimulant™ for Europe. If you are a cat guardian or veterinarian located in an EU country, we suggest you contact them first.
If you are a cat guardian located in Hong Kong, you may find Polyprenyl Immunostimulant™ available here.
If you are a cat guardian located in Qatar, you may find Polyprenyl Immunostimulant™ available here.

2 – Box insert
  Polyprenyl Immunostimulant™ information leaflet.
  Rhinotracheitis treatment brochure (optional).

 3 – Research papers
 Legendre, AM & Bartges, JW. Effect of Polyprenyl Immunostimulant™ on the Survival Times of Three Cats with the Dry Form of Feline Infectious Peritonitis (FIP). 2009. J Fel Med Surg, 11, 624-626.
 Legendre, AM et al. Polyprenyl Immunostimulant™ treatment of cats with presumptive non-effusive feline infectious peritonitis in a field study, 2017. Front Vet Sci, 14 February 2017.
 Legendre, AM et al. Polyprenyl Immunostimulant™ in Feline Rhinotracheitis: Randomized Placebo-Controlled Experimental and Field Safety Studies. 2017 Front Vet Sci, 27 February 2017.

How immunity protects your cat.

Polyprenyl Immunostimulant™ restores your cat’s innate immunity to fight viral infections effectively – something antivirals cannot accomplish. Find out why a strong immune system is essential in the fight against viral diseases such as FVR or FIP.

* Polyprenyl Immunostimulant™ is not or may not be available in a small number of countries due to country-specific regulations or contractual limitations.

Dosage calculator

Polyprenyl Immunostimulant® FVR dosage calculator

Vet Locator

Locate a veterinarian in your area with our locator map.


Visit our Frequently Asked Questions page for answers to the most common inquiries.