Feline Calicivirus Symptoms: Mouth Ulcers and Vet Care

Key takeaway: Feline calicivirus (FCV) most often shows up as painful mouth ulcers, drooling, sneezing and a reluctance to eat, and it is one of the most common causes of oral disease and upper respiratory signs in cats. If your cat is drooling, pawing at the mouth, or refusing food, book a veterinary exam promptly, because early assessment protects both comfort and appetite. FCV is different from feline herpesvirus and from Feline Infectious Peritonitis ("FIP"), so an accurate diagnosis matters before any treatment begins.

A cat resting comfortably at home.

What are the symptoms of feline calicivirus (FCV) in cats?

Feline calicivirus (FCV) symptoms usually center on the mouth and upper respiratory tract, and the most recognizable signs are mouth ulcers, heavy drooling, sneezing, and eye or nasal discharge. Many cats also become quiet, eat less, and develop bad breath because of oral pain.

FCV is a highly contagious virus that spreads between cats through saliva, nasal secretions and shared bowls or bedding. In multi-cat homes, catteries and shelters across Australia and New Zealand, it can move quickly from one cat to another.

The common signs of FCV include:

• Mouth ulcers on the tongue, gums, or hard palate

• Excessive drooling, sometimes with blood-tinged saliva

• Sneezing, nasal discharge, and congestion

• Red, inflamed gums and painful chewing

• Reduced appetite or complete refusal to eat

• Fever, lethargy, and reluctance to be handled around the face

• In some cats, lameness or a transient "limping" episode from joint inflammation

Severity varies widely. Some cats show only mild sneezing for a few days, while others develop deep oral ulcers and significant pain that stops them eating.

Why does my cat have mouth ulcers and drooling?

Mouth ulcers and drooling in cats are frequently caused by feline calicivirus (FCV), which damages the lining of the mouth and triggers painful sores on the tongue and gums. When these ulcers form, swallowing hurts, so saliva pools and spills out as visible drooling.

Cat mouth ulcers are not a cosmetic problem. They are a pain signal. A cat with oral ulcers may approach the food bowl, sniff, then back away, or cry out while trying to eat.

Drooling can have other causes too, including dental disease, a foreign object lodged in the mouth, kidney disease, or toxin exposure. Because the causes overlap, drooling always deserves a veterinary check rather than a guess at home.

If your cat has stopped eating well because of a sore mouth, gentle feeding strategies can help maintain calorie intake while treatment takes effect. Our guidance on safe foods and tricks to encourage a reluctant cat to eat offers practical, texture-based ideas that suit cats with oral pain.

What is cat stomatitis and how is it linked to feline calicivirus (FCV)?

Cat stomatitis is severe, widespread inflammation of the mouth and gums, and feline calicivirus (FCV) is one of the most consistently identified triggers. In stomatitis, the immune system reacts intensely to the tissues of the mouth, producing angry red, ulcerated areas that bleed easily and cause chronic pain.

Stomatitis symptoms often build over time and can include:

• Difficulty eating, especially dry food

• Weight loss from reduced intake

• Drooling, sometimes thick or blood-streaked

• Bad breath and an unkempt coat from stopping grooming

• Pawing at the mouth or head shaking

• A grumpy or withdrawn temperament linked to constant discomfort

Many cats with FCV-associated stomatitis carry the virus long term, and flare-ups can return under stress. Care focuses on controlling the virus, reducing inflammation, managing pain, and keeping the cat eating.

How is feline calicivirus (FCV) different from feline herpesvirus and FIP?

Feline calicivirus (FCV), feline herpesvirus (FHV-1), and Feline Infectious Peritonitis ("FIP") are three distinct diseases with different viruses, different signs, and different treatment paths, so telling them apart matters before anyone reaches for a medicine. FCV centers on mouth ulcers and oral disease, FHV-1 centers on recurrent eye and respiratory flare-ups, and FIP is a systemic disease caused by a mutated feline coronavirus.

Condition	Hallmark signs	Nature	Positioned product line
Feline calicivirus (FCV)	Mouth ulcers, drooling, stomatitis, sneezing	Highly contagious oral and respiratory virus	CaliciX line (EIDD-1931)
Feline herpesvirus (FHV-1)	Recurrent eye flare-ups, conjunctivitis, sneezing	Lifelong infection managed through flare-ups	HerpX (famciclovir)
Feline Infectious Peritonitis ("FIP")	Fluid buildup, weight loss, fever, eye or neurological signs	Systemic coronavirus disease	GS-441524 antiviral treatment

Because the signs overlap, cats are sometimes misdiagnosed. If your cat's picture does not fit neatly into one box, it is worth reading our overview of conditions commonly mistaken for FIP, which shows how careful diagnostics separate look-alike diseases.

Feline herpesvirus, unlike FCV, is a lifelong infection where care manages flare-ups rather than eliminating the virus. FIP, meanwhile, is where GS-441524 sits at the core of modern antiviral treatment, and CureFIP has supported more than 100,000 cats treated since 2019 across its FIP network.

When should you see a vet for feline calicivirus (FCV) in Australia and NZ?

You should see a vet for feline calicivirus (FCV) as soon as you notice mouth ulcers, persistent drooling, or a cat that is not eating, because oral pain and appetite loss can escalate quickly. Do not wait to "see if it passes" when your cat has stopped eating, as even a day or two without food is serious for cats.

Contact your veterinarian promptly if you notice any of the following:

1. Refusal to eat for more than 24 hours, or repeated attempts that end in backing away from food.

2. Visible ulcers on the tongue, gums, or roof of the mouth.

3. Heavy or blood-tinged drooling.

4. Difficulty breathing, or nasal congestion severe enough to block airflow.

5. Lethargy, fever, or hiding that is out of character.

6. Sudden lameness or reluctance to move alongside other signs.

In Australia and New Zealand, your veterinarian can confirm FCV through clinical signs and, where needed, laboratory testing, and rule out dental disease, foreign bodies, and other causes of oral pain. Early veterinary care also protects other cats in the household, since FCV spreads easily between cats.

Keeping a sick cat eating is a priority during any oral disease. Our practical appetite support advice for cats that are off their food covers warming food, softening texture, and reducing stress at mealtimes.

How is feline calicivirus (FCV) treated?

Feline calicivirus (FCV) treatment focuses on antiviral therapy for oral disease, pain relief, supportive nutrition, and management of any secondary bacterial infection, all directed by your veterinarian. Antibiotics do not act on the virus itself and are used only when a secondary bacterial infection is present.

For FCV oral disease such as stomatitis and gingivitis, the antiviral ingredient EIDD-1931 is used, and it is the active ingredient in the CaliciX line, the FCV-positioned product. In the CureFIP Oceania catalog, EIDD-1931 Oral Capsules are listed at AU$39.00, with 60 capsules per bottle.

The catalog dosing for EIDD-1931 Oral Capsules is 1 capsule (15 mg) per 2.5 kg body weight, every 12 hours, over a standard course of 60 days. This medicine is not intended for ocular or neurological cases or for cats that are not eating or defecating, and it is teratogenic, so it must not be used in pregnant or lactating queens.

Detail	EIDD-1931 Oral Capsules
Price	AU$39.00
Pack	60 capsules per bottle
Dose	1 capsule (15 mg) per 2.5 kg, every 12 hours
Standard duration	60 days
Not for	Ocular or neurological cases; cats not eating or defecating; pregnant or lactating queens

Always confirm the right plan, dose, and duration for your individual cat with your veterinarian before starting any antiviral. Body weight, oral pain level, hydration, and other health conditions all shape the safest approach.

Supportive care runs alongside antiviral treatment. That means pain control prescribed by your vet, soft and palatable food, fresh water, gentle warmth, and a calm, low-stress environment, since stress can worsen flare-ups.

A note on EIDD-1931 and FIP

EIDD-1931 also appears in FIP care, where it is paired with GS-441524 in a dual antival approach. GS-441524 remains the hero antiviral of FIP treatment, with a 92% success rate reported by UC Davis (Pedersen, 2019) for monotherapy injectables, while the dual antiviral combination of GS-441524 and EIDD-1931 reached 78.3% remission in Li and Cheah 2025.

These figures belong to FIP, not FCV, and are shared here only to explain why the same ingredient family appears across our resources. If your cat's diagnosis is FIP rather than FCV, our guide on why caregivers in Australia are choosing dual antiviral therapy and our full FIP symptoms guide for Australia and New Zealand explain the difference in detail.

FAQ

What are the first signs of feline calicivirus (FCV) in cats?

The first signs of feline calicivirus (FCV) are often sneezing, mild eye or nasal discharge, and small mouth ulcers, followed by drooling and reduced appetite as the ulcers become painful. Because early signs look like a mild cold, watch closely and see a vet if ulcers or drooling appear.

Are feline calicivirus (FCV) mouth sores painful for my cat?

Yes, feline calicivirus (FCV) mouth sores are genuinely painful and are a common reason cats stop eating, drool, and paw at their faces. Pain control from your veterinarian, combined with soft food, helps keep your cat comfortable and eating while treatment takes effect.

Can feline calicivirus (FCV) go away on its own?

Some cats clear the acute signs of feline calicivirus (FCV) within a couple of weeks, but others carry the virus long term and experience recurring flare-ups or chronic stomatitis. Because outcomes vary and mouth pain can stop a cat eating, veterinary assessment is important rather than waiting it out.

Is feline calicivirus (FCV) contagious to other cats in my home?

Yes, feline calicivirus (FCV) is highly contagious to other cats and spreads through saliva, nasal secretions, and shared bowls and bedding. Separate an affected cat, wash bowls and bedding, and ask your veterinarian about protecting the other cats in your household.

Is feline calicivirus (FCV) the same as FIP?

No, feline calicivirus (FCV) is a contagious oral and respiratory virus, while Feline Infectious Peritonitis ("FIP") is a systemic disease caused by a mutated feline coronavirus and treated with GS-441524. They are different diseases with different signs and different treatment paths, so an accurate diagnosis is essential.

If your cat is showing mouth ulcers, drooling, or a lost appetite, the kindest next step is an unhurried conversation with people who understand these viruses. You are welcome to explore treatment options and reach the CureFIP Oceania team to learn more, and to talk through the right plan with your own veterinarian before starting anything.