What is Rodent Ulcer in Cats and How Do You Treat It?

Rodent ulcer in cats isn’t caused by what you may think it is — and you might even be able to cure it at home, naturally. Here’s how!

An orange cat who's sleeping or sick.
An orange cat who's sleeping or sick. Photography ©infinityyy | Getty Images.

Rodent ulcer, which also goes by many clinical names, including eosinophilic granulomas, is a complex, highly unpleasant skin condition that my poor cat, Murphy, developed. While veterinarians commonly treat rodent ulcer with a regimen of steroids and, in the event that the sores become infected, antibiotics, I cured him in record time with natural remedies and some simple lifestyle changes.

What causes rodent ulcer in cats?

Rodent ulcer in cats.
Photography courtesy Alissa Wolf.

The name ‘rodent ulcer’ is misleading, as rodent ulcer is not caused by contact with rodents. Rather, it’s an allergic reaction with any number of causes that results in unsightly, often painful lesions around a cat’s lips, chin, inside the mouth and, in some cases, other parts of the body. It’s most common in younger cats aged two and under, and female kitties.

The main causes of rodent ulcer are allergies to fleas, foods, the chemicals in plastic and rubber bowls, environmental pollutants, synthetic ingredients in cat litter or having a compromised immune system, such as cats with feline immunodeficiency virus (FIV). If left untreated, this can result in permanent disfigurement. This was especially upsetting to Murphy, who takes great pride in his dashingly handsome appearance. So quick action was in order.

How Murphy got rodent ulcer

I have always fed my cats high-quality natural, grain-free foods. Plus, I have consistently used glass bowls, which I wash after each use in the dishwasher, for their food and water. I also give them filtered water, use natural cat litter and safe, eco-friendly household cleaning products. And Murphy never had fleas.

But after getting laid off from my job in the summer of 2014, I could no longer afford the natural cat foods, which are pricey. So I switched my cats to Fancy Feast Classic. As this does not contain wheat gluten, this seemed like a reasonable compromise. Then, about a month after I began feeding this to my cats, Murphy developed inflamed, oozing sores along his chin and the corners of his mouth.

As I have written extensively about pet health and wellness, I immediately recognized this as rodent ulcer. Via a process of elimination, I determined that switching him to a different brand of cat food was the culprit. So I set about changing his diet and getting him on a regimen of natural remedies.

How Murphy was cured of rodent ulcer

A black cat with a tin of wet food.
Photography courtesy Alissa Wolf.

As I mentioned previously, veterinarians have traditionally treated rodent ulcer with steroids and antibiotics. But as someone who is a huge proponent of natural pet care, I opted to first try some holistic remedies with the approval of a friend, Dr. Cathy Alinovi, a veterinarian who practices integrative medicine in Indiana and is always happy to give me free advice.

First, I completely eliminated the Fancy Feast from Murphy’s diet. As I had recently reviewed a new line of natural canned cat foods called Dave’s, which is one of the more reasonably priced brands, I switched him to that.

Next, I placed him on a regimen of the immune-boosting supplement L-Lysine in the form of 250-milligram Pet Naturals of Vermont Cat Chews, which I gave him twice daily, and one-half teaspoon of colloidal silver, a mineral that acts as a powerful natural antibiotic, which I mixed with his food once daily. I purchased the treats from a pet store that specializes in natural products, and I got the colloidal silver, which is inexpensive, from a health food store.

In addition, I treated Murphy’s rodent ulcer sores topically by periodically spritzing them with some colloidal silver, which I poured into a small spray bottle. Plus I lightly dabbed the lesions with organic coconut oil, which has antibacterial properties, and misted the affected areas with a nifty spray product called Epic Pet Health Repair, which I also sprayed into his food and water once a day.

The latter is a line of holistic sprays and drops comprised of diluted vitamins and minerals in water with electrolytes, which treat a variety of pet health and behavior issues. The line was developed by a civil engineer turned holistic chiropractor named Dr. Amy Swartz of Seattle, Wash., who had sent me some samples to review a few months before Murphy developed rodent ulcer. This certainly came in handy, as the spray alleviated Murphy’s discomfort upon immediate contact.

The at-home treatments for rodent ulcer worked!

A happy black cat wearing a bow tie.
Photography courtesy Alissa Wolf.

When I initially embarked on this treatment regimen, I vowed that I would resort to a trip to the vet and would agree to place my kitty boy on steroids in the event that the natural approach did not work. Lo and behold, it did. Within a week, the rodent ulcer sores began to abate. By week two of the treatment regimen, Murphy was completely cured of rodent ulcer and back to his usual suave, handsome self.

What to do if your cat develops rodent ulcer

My experience is unique, because I have an extensive background in researching and writing about pet health issues. I also have the advantage of having a veterinarian friend who readily supplies me with free pet medical advice.

However, most people aren’t in my position. So I do advise a trip to the vet if you suspect that your cat has rodent ulcer — or any other health issue, for that matter. But even if you do opt to place your cat on meds, complementing the treatment with some natural remedies can’t hurt, and may very well help to accelerate the healing process.

Tell us: Have you ever used natural remedies to treat your cat? Have you ever dealt with rodent ulcer in cats? Tell us how it went in the comments!

This piece was originally published in 2014.

Thumbnail: Photography ©infinityyy | Getty Images.

About the author:

Alissa Wolf is an award-winning journalist and lifelong animal lover who lives near Atlantic City, N.J. with her cats, the dashingly handsome Murphy – the proud owner of a vast collection of bow ties – and Lily, an occasional feline fashion model. She writes about a variety of pet topics on her blog Critter Corner. Follow her on Facebook and Twitter.

Read more about cat health and care on Catster.com:

39 thoughts on “What is Rodent Ulcer in Cats and How Do You Treat It?”

  1. Hi there.
    I’ve recently been dealing with this and just wanted to share because I’m finally getting some results. My cat, for some reason, developed rodent ulcers after I switched his food to Orijen Red cat food. He has had grain free food his whole life, has ceramic bowls, etc. etc… He had a nasty one growing on the left side of his lip (it’s still there) and a smaller one on the right side was starting to develop. Anyway, before finding your protocol I took him to the vet and the doc suggested antibiotics, steroid and a medicine called Atopica. I went ahead and did the antibiotics, said no to the steroid.. and after reading the pamphlet for Atopica and also seeing some horror stories online about it I decided to just wait and see if the antibiotics would do anything. At this time I had switched him back to his original food for about a week. His smaller growth disappeared shortly after the antibiotic, maybe after a week or so but the bigger one showed no sign of leaving. I then found your protocol because I didn’t want to give him Atopica (my cat is 2 btw). I put him on the protocol for about a month and unfortunately it was still not showing any improvement. I then saw someone leave a comment about a ointment called silver honey. I started applying that alongside the protocol and STILL no improvement, but on the plus side it wasn’t getting worse either. It was just there, not shrinking, not growing. Finally, I remember I was swishing some hydrogen peroxide in my mouth a few years back for an infected tooth that really helped stop the swelling/puss. So I decided that it can’t hurt to try, especially cause I’ve tried all that I can. I have been using an ear swab to apply 3% hydrogen peroxide on the ulcers. I’ve been doing it probably 4-5 times a day and also applying the silver honey once every other day. It seems to be finally improving. It’s not gone but I’m definitely noticing the swelling and size decreasing and this has been without your protocol the past couple weeks, which I’m sure was helping as well. I just want to thank you for the information and also wanted to share this so that it may also help someone else.

    1. Thanks for sharing your experience as we struggle against them all the time. I did notice you said ceramic bowl. Everyone lists get rid of plastic but ceramics get micro cracks that hold bacteria we don't even use it for ourselves after seeing the studies. Metal bowls clean up best. Good Luck T

  2. Hi Alissa, I just wanted to say thank you so much for this article as it has truly helped us manage our cat Millie's rodent ulcers (she is a Russian Blue mix). She began developing them around her mouth, chin, and gums at 1 year of age after no significant change in her food, litter, or environment. We ended up having to take her to the vet for steroid shots again and again after failing to find the source of the allergic reaction. It has been hard given we also have a dog and therefore potential outdoor allergens are next to impossible to eliminate. The next course of action was putting her on Atopica, which only caused our Millie to stop eating and lose a concerning amount of weight.

    All of this backstory is just to say that after giving her the L-Lysine treats and putting Silver Honey (another product mentioned by a commenter here) on the spots twice a day over the course of 7 days, they began to resolve on their own! They were gone for almost another year before a recent flare-up brought me back to this site and I'm happy to report the same regiment looks like it has helped again. I wanted to express my thanks to you for writing about this treatment and let others know how it has really worked for us as well!

  3. Roxanne Bergadine

    This is not about rodent ulcers, but I did use a natural treatment of another sort on a kitten with an extremely bad eye infection which turned out to be highly successful. In the fall of 2019, my boyfriend found a litter of kittens under the seat of my father’s riding lawnmower. They all had varying degrees of upper respiratory infection, especially infecting their eyes, which were all oozing goo or pasted shut. I decided I had better intervene, or they’d all end up dead or blind. Having been through this before a number of times, I was surprised to find that there was one kitten whose eyes I just couldn’t get open for anything. I decided to consult my vet about this because I needed amoxicillin to treat the kittens uri anyway. Well, she wasn’t in that day, but another woman who works at the desk told me to use coconut oil to get the kitten’s eyes open (and by the way, it was also antibacterial). I had my doubts about this, but I was desperate. They always say you can get coconut oil in a jar, heat it up slightly, and use that in the affected cat’s eyes, but I used the pills instead (gelcaps with liquid coconut oil in them). I snipped one open, applied it liberally to the little orange one’s eyes, and hoped for the best. It worked like a charm. (I used it on the other kittens’ eyes as well for a short time, with more success.) All of the kittens recovered from their infection, none of them turned out blind, and little Leander (the one whose eyes I couldn’t get open at all initially), the runt of the litter, is now a big strapping orange tabby and my pride & joy. I just had to keep that one, and you would have too.
    (By the way, the kittens were also treated with amoxicillin and Gentamicin eye drops, which I also highly recommend for this sort of situation.)

  4. your suggestions on what worked for Murphy, worked great for my cat. I also decided to make his food, so I knew exactly what he was eating. He has been doing great for 4 years. Here recently he developed a sore on his foot pad, then the ulcer on his lip came back. I got it cleared up, but now the other back foot has developed a ulcer. Any other suggestions beside the Murphy treatment to help his foot pads. Thank you.

  5. Booger’s Mom

    HI Alyssa, I hope you are still reading this.
    My new persian kitty, now a vibrant 1 year old, developed the Rodent Ulcer several months ago. My friend and great Vet presribed a steroid for him that started him on a full dose for 10 days, then a 1/2 dose every other day for 2 months while giving him 1/2 capsule of Cell Advance 440 daily to try and boost his immune system. After the steroid doses were done, I was then to watch for the return of the ulcer and time it. Well I think it was destined to happen that the ulcer was already on its return path near the end of the meds because 2 days after I finished the meds, he got a whopper on his top lip again. omg.

    Has ANYONE found a magic bullet for this? Hopefully you still have your dashing boy Murphy.. and if so, has he continued to struggle with ulcers and what are you feeding him and doing for him today to keep these awful things at bay?


  6. Thank you SO much for this suggestion! I was taking my three-year-old cat to the vet every 3 to 5 months for the past year. Each time giving him a steroid injection. We made a switch to his food and he seemed to be doing really well. 2 weeks ago he ended up with another ulcer. Knowing that the steroid only masks the situation and won’t cure it, I really did not want to have to bring him to the vet. I read your article and decided to purchase L-Lysine treats and colloidal silver from chewy.com. There was a delay in shipping because of COVID- 19. With his ulcer getting worse, I found Silver Honey – An antimicrobial gel spray at Petsmart! I used a q-tip and applied it to the ulcer 3 times A-day for 3 days and it is almost non existent at this point!! So relieved to have found a natural at home remedy for him!
    My only question is should I give him the L-Lysine treats for maintenance or only when he has a flare up?
    Thank you again for your help!

        1. i started this regimen on her, and she has new spots, or its spreading. is it suppose to get worse before it gets better? its only been 3 days.

        2. I used silver gel that has 55 PPM and a dab of 1% hydrocortisone cream and his ulcers seems so much better he’s a seven-month-old orange tabby so I was highly surprised when I saw that he had this issue because he’s so young so far so good, I had started the silver in hydrocortisone before I read the article I have not tried the lysine yet just because I have not been able to find it in the stores

    1. I am so happy to hear that your kitty is doing better! I would not give the L-Lysine for maintenance. When used for treating issues, I would only give it for 7-10 days at a time. Hope this helps.

  7. Hi there , replying from Canada our 2 year old girl, sweetheart aka biggie butts that came to us as a stray has this issue only develops on front paw and a small spot in her side.
    We went to the vet last summer, antibiotics and topical spray was used on her vet recommendations. It went away till Christmas now is back. I’ve read stress will also cause this to flare up? My one son was over for the holidays and her flare up happened after he left as he tends to agitate cats.
    We switched her to simply nourished salmon recipe in the summer all was going well.
    I’m going to try colideal silver on her, as for lysene. Alissa, is there a place in Canada I can purchase it? Local pet store or I would need to purchase online? If so can you provide me the link?
    Thank you for posting this as I have been trying to find info for natural remedies for rodent ulcer.

    1. Found the lysene and picked up colideal silver, will see how it works for her. Thanks again Alissa for the fantastic post

  8. We have a 17lb Chantilly/Main Coon mix and he started developing rodent ulcers on the upper lips last March. Our vet has prescribed steroids and Prednisone several times and each time the ulcers go away for a bit, then return. So once I found this article, we decided to try the holistic approach. So far, the ulcers haven’t responded well to the Lysine/Silver/Epic spray. He’s eating all the natural foods just fine and taking the meds fine as well, but the ulcers haven’t gone away. It’s been one week now. I’m not sure if there’s a period of time that they “get worse before getting better”?

  9. Hi! Thank you for this info! My guy has always gotten these seeping his lips but now it seems he has this on his neck area? It seems to be a bald spot. It’s not bleeding but it’s a raw spot and the hair is missing in a circular area by his throat?

  10. Hi Jennifer. Murphy never appeared to be any pain when he had this. But using the Epic spray along with the other remedies I recommended definitely expedited the healing process. I hope it works for Willow.

  11. My kitten that I adopted from stray cat blues is only 4 months old, but she started developing her first ulcers in the corners of her mouth around 12 weeks old. She has had 3 bouts with them already. We have had her on antibiotics and then steroids for her previous ulcers and they went away, but they come back every couple of weeks. She is on blue buffalo grain free, limited ingredient kitten food, using stainless steel bowls, and does not have fleas. She takes 1 lysine 250mg a day, she can only take 1 because she is still a kitten. She eats, and drinks with no problem and is very energetic and active, but I cant figure out why she keeps getting the ulcers. I would like to try the colloidal silver, but I was unsure if it was safe for a 4 month old kitten, and if so how much I should give her.

    1. Hi Tammy:
      I use Sovereign Silver 10 PPM for my cats. It comes in drops, spray and gel. I would advise asking your vet before you administer this. Otherwise, you might start by applying the gel topically to the ulcers three times a day. Be sure to thoroughly wash and dry the area before each application. Hope this helps.

      1. Thank you, I will check with my vet first, and hopefully they will say it’s ok to try. I would really like to try a home remedy approach as opposed to continuously taking her to the vet for steroids and antibiotics.

          1. I just wanted to give you an update and say thank you! My vet gave the ok and my kitten luna has been on the colloidal silver for about 6 days, and her latest bout of ulcers have almost completely disappeared! I purchased the sovereign silver 10ppm off amazon in spray form and have been applying one spray in the morning and one at night. I am thrilled that we could get her back on track with this remedy instead of taking her to the vet for more meds. We have pretty much narrowed her allergy down to grains, and have her on an all grain free diet. I am pretty sure this last bout of ulcers occurred because she got into our other cats regular food. We are feeding them separately now to avoid it happening again, and will keep the colloidal silver handy just in case she has any more occurrences in the future. Thank you again for the great advice, I really appreciate it!

        1. That’s paw-some news! I am so happy that your kitty is doing much better. Please give Luna my best regards.


          1. Hi Alissa, My cat Willow is battling IBD, even though we are on grain-free canned food. We finally seem to have the IBD under control, but now she has developed an ulcer on her lip, which she hasn’t had in 6 years. Last time we used diluted Frankincense oil, but it’s not working this time. I want to try some of that Epic spray, but I’m wondering if you would share how you knew it was giving Murphy pain relief upon contact? Thanks!!

    2. Tammy, I have exactly the same issue with my kitten. She is 7 months old, and getting ulcers on her lip every 2,3 weeks. She has been receiving steroids every few weeks but I can’t see it as a long term solution as she is still a kitten.
      We just did a biopsy and I am hoping that might give us some answers.
      I will definitely try with lysine but have to do more research on colloidal silver as she is still kitten.
      Please let me know if you happen to discover solution for this issue.

  12. My car has this. Every mo th we make a trip to the vet where he injects him with antibiotics and gives him strong hold. This time his ears got so bad I thought we would need to go again but I decided I would treat him with castor oil and colloidal silver. After 3 days, his eye is open and the lesions on his ears are healing. Can you use human l-lysine ? He does eat kibble but grain free and high meat but I’m going to get him on something better. My other cat is addicted to the food and is getting fat , so I need to change the way they eat for sure. I’ve researched Raw for some time but just haven’t got round to it yet.

    1. Hi, Sarah:
      I am so glad that I was able to help your kitty! You can get L-lysine at the health food store. For an adult cat, give them 250 milligrams twice daily. You can just sprinkle it in wet food. Hope this helps!

  13. I’m highly interested in a natural way to help my poor cat Teddy get rid of his rodent ulcers . Please send my her info in a list form of what to get and where I could get it ? Thank you ever so much . Joanne and Teddy

    1. Alissa – Great article. I am surprised to read that the change in foods was what brought on the rodent ulcers in Murphy. I have heard that certain cheap grocery store foods aren’t great, but would never have imagined that it could cause the ulcers! Did Murphy ever get the ulcers back again? Joanne – We have also found a great silver spray that works. It is part of a supplement kit from Ask Ariel. It is called the Immune Support Kit. The package is a little pricier than the sprays I could find on amazon, but it has three products that work in different ways. They have just the spray too. Since the steroids and antibiotics from the vet only last for so long and then the ulcers come back worse than before, it was important to find something natural that could be used long term. It ends up saving money, because there are fewer trips to the vet.

      1. Hi Laura:

        Yes, food makes a world of difference! Thankfully, Murphy never got rodent ulcer again. He does occasionally get scabs from dermatitis, and I treat him with the colloidal silver gel. It works great. I am not a big fan of steroids, except under dire circumstances. I am happy that natural treatments have worked for your kitty. Thanks for sharing.


  14. Do you have a website for your friend Amy’s site. I’m interested in reading more about her products
    Thank you

  15. My one kitty had egc, she was allergic to fish. So I did a LOT of research and found there are only 3 cat foods commercially available that do not have fish in them. I no longer have Miss Indie anymore, but i still feed the same food to my current kitty. (Natural Balance)

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