A Licorice Root Compound May Help Fight FIP — But It’s Not a Treatment Yet
FIP antiviral research just got a small but encouraging boost. Scientists have found that a compound taken from licorice root — called glycyrrhiza polysaccharide — can block the FIP virus from infecting and multiplying inside cat cells in the lab. This is very early research, done in a dish rather than in actual cats, but it adds a new name to a short list of substances worth studying further for this devastating disease.
If your cat has been diagnosed with FIP, or you simply want to stay informed about what researchers are exploring, here is what this study actually found — and what it does not mean yet.
What Makes FIP So Hard to Treat
Feline infectious peritonitis, or FIP, is a disease caused by a virus called feline coronavirus. Most cats that carry this coronavirus never get sick from it. But in a small number of cats, the virus mutates inside the body and becomes the FIP virus — a much more dangerous form that attacks the immune system and vital organs.
For a long time, FIP was considered almost always fatal. That changed in recent years when a drug called GS-441524 (an antiviral medication) proved highly effective in treating many cats with FIP. However, access, cost, and the need for long treatment courses remain challenges for many cat owners.
Because of this, researchers are actively looking for additional antiviral options — substances that might fight the FIP virus in new ways or at lower cost. That is the kind of search this study was part of.
How the Study Was Done
The researchers used a cell culture model, which means they grew feline kidney cells in a lab dish and exposed them to the FIP virus. Think of it like a controlled experiment inside a test tube — no cats were involved, just isolated cells.
To make the virus easier to track, the scientists used a special version of the FIP virus that glows green under a microscope (thanks to a protein called eGFP added to the virus). This let them see clearly whether the virus was successfully infecting and multiplying inside the cells — or whether a test substance was stopping it.
They then tested glycyrrhiza polysaccharide — a complex sugar molecule extracted from licorice root — to see if it could block the virus.
What the Study Found
The results were notable for early-stage research:
- Glycyrrhiza polysaccharide blocked the FIP virus from attaching to the cells. Before a virus can infect a cell, it first has to stick to the cell’s surface — a step called adsorption (think of it like a key trying to fit a lock). The compound interfered with this step.
- It also slowed the virus from copying itself inside the cells. Even when some virus got in, the compound reduced how well the virus could replicate and spread.
Together, these two effects suggest that glycyrrhiza polysaccharide may work at more than one point in the infection process — which is a useful quality in a potential antiviral.
What This Means for Cat Owners
This Is a Lab Finding, Not a Treatment
It is important to be direct here: this is not a treatment for FIP. The study was done entirely in cell cultures, not in live cats. The researchers themselves described this work as a basis for further research — a starting point, not a finish line.
Many substances that show antiviral activity in a lab dish do not pan out when tested in animals or people. The road from “works in cells” to “safe and effective medicine” is long and requires many more studies.
Do Not Give Your Cat Licorice Root Supplements
Even though the compound comes from licorice root, giving your cat licorice root supplements or herbal products will not treat FIP. The compound used in this study was purified and tested in specific, controlled conditions. Herbal products are not the same thing. Some can actually be harmful to cats. If your cat has FIP, please work with your veterinarian and explore evidence-based antiviral options.
When to Talk to Your Vet
If your cat has been diagnosed with FIP, or you notice symptoms like:
- Fluid building up in the belly or chest
- Persistent fever that does not go away
- Loss of appetite and rapid weight loss
- Lethargy and weakness
…you should talk to your vet right away. Approved antiviral treatments for FIP do exist and are worth discussing with your veterinary team. Your vet can walk you through current options, costs, and what to expect.
Study Limitations
This study was done entirely in the lab — in isolated feline kidney cells, not in living cats. While the cell model is a standard and accepted starting point in antiviral research, it cannot tell us how a substance would behave inside a cat’s body, whether it would be safe, or whether it would reach the right tissues in effective amounts. No animals were used, and no clinical outcomes were measured. Much more research is needed before any conclusions can be drawn about real-world effectiveness.
The Bottom Line
A new lab study found that glycyrrhiza polysaccharide — a compound from licorice root — can block the FIP virus from infecting and replicating in feline cells. This adds a promising candidate to the list of substances researchers are studying as potential FIP antivirals. But this is very early science, and it is not a treatment recommendation. If your cat has FIP, the best step you can take right now is to work closely with your vet on proven treatment options.
Research like this is how new medicines eventually get discovered — one careful study at a time.
This article summarizes peer-reviewed research for educational purposes. Always consult with your veterinarian for personalized advice about your pet’s health and behavior.