Treating Resistant Warts with Cantharidin

Written by Valerie Hanft, MD, Board Certified Dermatologist on October 19, 2018 38 Comments

Cantharidin wart treatment

Of all the common skin conditions, patients often cite warts as one of the most troublesome and undesirable. A wart is a viral infection of the skin. While generally harmless, warts can grow on nearly any part of the body. On the face and tops of the hands, warts are raised. On the soles of the feet, the tissue becomes thickened from the pressure of standing and the warts (called plantar warts) are flatter. Warts have a rough surface on which tiny, dark dots can often be seen.

Two of the easiest and most frequently used methods of getting rid of a wart are topical salicylic acid treatments and cryosurgery (freezing the wart off using liquid nitrogen). There are, however, some warts that resist both treatments. In these cases, there is another option for eliminating the wart: Cantharidin.

What Is Cantharidin?

Cantharidin is an odorless and colorless chemical derived from blister beetles. In nature, male blister beetles secret cantharidin during mating. The female blister beetle then uses the secretion to cover her eggs in order to protect them from predators. (Source)

In large doses, cantharidin is a powerful poison and burn agent. For dermatological purposes, properly dosed cantharidin can be used for causing strategic blistering of the skin.

How Does Cantharidin Remove Warts?

When topically applied to a wart, cantharidin causes controlled blistering underneath the skin. It also triggers the release of an enzyme which breaks the bonds that hold skin cells together. Eventually the blistering below the wart combined with a deterioration of cellular adhesion causes the wart to become detached and peel off.

How Is the Treatment Performed?

Cantharidin should be administered by a physician who has experience in its use. The doctor “paints” the cantharidin directly on the wart before covering it with a bandage.

How Effective Is Cantharidin?

Cantharidin is a very effective wart treatment, often working well on warts that resist other treatments. The application of cantharidin is less painful than surgical excision and there is no scarring, making it a great option for young children or on warts that appear on highly visible areas.

While cantharidin typically removes a wart in a single treatment, some patients may need follow up applications if the wart isn’t gone after one treatment.

Are There Any Side Effects?

The side effects of wart removal via cantharidin are typically mild and can include tingling, itching, or burning sensation around the treatment area over the first few hours after being applied. Since cantharidin can cause breaks in the skin, infection is possible, but extremely uncommon if the site is properly cared for and kept clean. The skin may also feel tender for 2-5 days following treatment. During this period some patients may find it painful to apply direct pressure on the area being treated. We encourage patients to discuss the potential for pain with their dermatologist prior to undergoing a cantharidin treatment.


Valerie Hanft, MD

Valerie Hanft, MD is Board Certified by the American Board of Dermatology and is a member of the Travis County Medical Association. Dr. Hanft received her Dermatology specialty training at the University of Michigan. Her professional interests are in pediatric dermatology, clinical research and medical dermatology. Dr. Hanft sees patients at our Westlake location.

38 Responses to “Treating Resistant Warts with Cantharidin”

  1. Avatar Kathleen says:

    I just had Cantharidin applied to cluster of plantar warts under big toe, one on foot pad and one on adjacent toe. one hour later the pain was really high and was difficult to control for two days and walking for four. I couldn’t believe someone had done this to me with no warning. The podiatrist had said “Take a couple of Advil for pain” I used ice and lidocaine gel just to make it through the weekend. Be aware that this can happen. And why?

    • Avatar Cindy B says:

      Agree could not put any pressure on foot after using this treatment on the ball and heel of the foot for a week. While it works be prepared.

    • Avatar Ephraim says:

      Had the same experience with this treatment for a planters wart on the side of my heel. Had the treatment Wednesday morning, felt no pain until about 8pm that night, and haven’t been able to walk since eating up Thursday morning. This is 20x more painful than any liquid nitrogen treatment I’ve had for a planters wart. It’s Friday night and I’m still in agony.

      • Avatar Jo says:

        Hey Ephraim,

        I’m curious when your pain finally subsided? I’m nearing the end of day three, since my treatment, and I still can’t walk. I have an event that I need to be walking perfectly for, and it’s in 6 days. Getting a little nervy!

    • Avatar Steve says:

      I had beetlejuice applied to the ball of my foot six days ago. The pain hasn’t lessened at all. It’s excruciating. No one warned me this could happen. I’m praying it gets rid of the wart because I can’t suffer through this again. If it’s still hurting this bad in the morning, I’m calling the doctor to have words. It’s not just hurting when I put pressure on it. When I prop it up at rest, it’s literally throbbing.

  2. Avatar Mark says:

    Great post about wart treatment. Thanks for sharing.

  3. Avatar Dallas says:

    I’m on my second round of this treatment and it hurts. There is nothing mild about pain. It’s on the pad of my food just underneath the big toe. Dont minimize this. People need to know to plan for this procedure. I was on crutches the first few days because it was unbearable to put direct pressure on it.

    • WD Staff WD Staff says:

      Hi Dallas,

      Thanks for reading our post and submitting your comment for our community. I’m sorry to hear about your post treatment pain and think our readers will benefit from your testimony. We’ve added the statement: “The skin may also feel tender for 2-5 days following treatment. During this period some patients may find it painful to apply pressure on the area being treated” to better illustrate the potential for such issues.

      While many of the patients we treat with Cantharidin cite minimal pain when the come back for further treatment, we agree with your viewpoint and we did not intend to minimize anything.

      Thanks again,
      WD Staff

  4. Avatar Rachel says:

    I’ve been worrying about warts on my neck and breast area, that’s why I’ve been searching for ways on how to get rid of these. Luckily, you shared Cantharidin be used for causing strategic blistering of the skin. Maybe this can solve my skin problem, but if not maybe there’s a clinic that I can go to in which can help in eliminating these unwanted warts.

  5. Avatar Alyshia Kalis says:

    My son received this and I don’t think there’s anything mild about this. Is it normal for it to “burn” so badly after washing?

  6. Avatar Renee says:

    I agree. There is nothing mild about this treatment. I can an outbreak in my inner thighs and used this treatment. How long is the burning supposed to last?

  7. Avatar Courtney says:

    I had several planters warts removed The foot dr cut them out with out numbing me then applied this medicine. It has been almost a week now and the pain has been awful and I have developed a staph infection in both my feet

  8. Avatar Ryan says:

    Just had this procedure and the pain is almost worse than the plantar wart itself. When it starts to blister it really starts to burn bad. Had to call my Dr. To make sure this was normal. On day 2 hopefully this will get better. Not sure if I should pop the blister to relieve the pressure but very uncomfortable

  9. Avatar Tiffaney says:

    I just had my 8th treatment ( every two weeks) on my foot and I can agree there is nothing close to mild pain about this. The pain is severe for up to two days. I’ve finally hit my limit with it and when I go back If the wart isn’t gone, I’m going to have to find a new treatment. I’m not suggesting it doesn’t work, I’ve tried everything else prior to these treatments and I do feel like it’s a huge improvement…..but it is not for the weak so if you go this route, be ready!!!

  10. Avatar Laura says:

    Thank you both for posting your comments. I’m now on my fourth cantharidin treatment for stubborn plantar warts on the ball of my left foot and heel of my right foot and I was wondering if the pain I experience is abnormal or if I just have a low pain tolerance. The pain I feel the evening after my cantharidin treatments is so severe I have trouble sleeping. I’m unable to walk for two days. The pain becomes more bearable on the third day and on the fourth I’m pretty much back to normal. I am seeing improvements as others have said but I definitely would not describe the pain as mild for at least the first two days. I’m going to inquire about a numbing cream. I’m hoping I only have to endure two or three more treatments tops.

    • Avatar jenny says:

      I am on my 5th day and I literally have a visceral whole body pain when the area is touched. Weirdly, nothing has changed, it looks exactly the same, only 20x more painful! I am praying it calms down soon. It’s worse at night and in the morning because my foot is slightly swollen. As I go through the day, if I walk on it, the pain is unbearable. Please tell me this is normal.

  11. Avatar Val k says:

    Who writes this??? On my 3rd treatment. For 3 days you’ll reach max allowed dosage on any OTC painkillers. For 3-4 days you can’t walk. For one whole week you will have issues with treated foot. Sadly, it’s the only thing that works for me so I have to suck it up

    • WD Staff WD Staff says:

      HI Val,

      Thanks for your feedback on this. We wrote it with feedback from a few of our patients. However it does seem that the pain spectrum from treatment does range pretty greatly.

      We appreciate you sharing your experiences with our community, it will be very valuable to readers!

      WD Staff

  12. Avatar Leif says:

    Our son had a couple warts on the underside of his middle toe. The dermatologist skipped right past trying to freeze it and used a blister beetle treatment (cantharidin).

    The pain is definitely awful and looking at these comments, that’s the norm. Boy was in tears from discomfort for days. The *entire* area that blistered turned into one massive wart complex that is now the entire underside of his toe. It cracks in the middle where it bends and he’s miserable. Doctor was shocked and we’ve been treating this wart with acid and filing it down regularly, but it’s been six months and not very much improvement.

    We’re extremely unhappy our son is in daily pain thanks to this stuff. Worried the wart is so deep that surgery would be required at this point.

  13. Avatar Lauren says:

    Agreed with the previous posters, this is excruciating. I’m just had my 2nd treatment yesterday. For my 1st treatment I was told to leave on for 24 hours, which I was able to do without pain, but then the following 4 days were so painful I could barely walk. For my 2nd treatment, I made it 3 hours before the burning started, then washed it off when I couldn’t get ahold of my doctor. I came here looking for advice – so many sites related to this procedure only mention “mild discomfort”, but the comments here clearly tell the story as it relates to my experience. I would compare the sensation to being jabbed with a red hot poker at each lesion. It is a continuous burning & throbbing, otc pain relievers seem to downgrade it to a dull ache for about 3 hours before it returns. Sleeping last night was troublesome & walking this morning is out of the question. Can the dermatology community please come up with better aftercare or treatment modality for this!?

  14. Avatar Ellen says:

    I’ve had three treatments now and although it’s painful I feel it’s worth it. I’ve had this wart on the outer side of my foot for 4 years as my former doctor told me it was a corn. I work a job that has me standing on my feet for 8 hours a day. At times it’s crazy painful but I’m willing to have this treatment.

  15. Avatar Mike says:

    On my 2nd round of Cantharidin, the blister appeared but it pretty much ripped off since the wart was on the palm of my hand. More discomfort than any pain. Now I’m unsure if I should leave this uncovered to dry out, or should I cover the area with neosporin and a bandaid….

  16. Avatar Michelle johnston says:

    Just had my first treatment yesterday,very painful, burning,my job requires me to stand on my feet for a lengthy amount of time,and alit of walking,don’t know if I’ll be able to do it again tomorrow.just know this procedure is painful,it’s definitely not a mild pain,suppose to blister within 24 hours,that hasn’t happened yet.

  17. Avatar TA says:

    Had one on my heel, which started hurting about 10 hours after the application of cantharidin. I basically couldn’t put pressure on that foot for 3 days, and it was probably around 7 days before I didn’t notice the pain. It didn’t alter my lifestyle per se, but I concur with the “caveat emptor” emphasized by other commenters–the expectation should be it is a painful, non-trivial, and potentially short-run-lifestyle-altering treatment.

    I’m just glad I hadn’t mentioned the wart to the doctor before the marathon I had run the month prior, as I had no idea the treatment would be significant at all until it happened.

  18. Avatar Steve S says:

    My doctor has been using this for treatment on my plantar wart, and he is adamant that I wash it off after only one hour of application. I have not had the excruciating pain that others have described. YMMV.

    • Avatar jenny says:

      Thanks for that info. I wasn’t even told to wash it. I showered with the band aid on and it must have spread to the surrounding area of the foot. Needless to say, I am suffering at day 5.

    • Avatar David Flannagan says:

      This treatment has no standards of application or time of leaving the acid on for best results. I’ve read to leave this very caustic medication on from anywhere from 1 hour to 48 hours. My podiatrist told me to leave it on for a minimum of 24 hours! Fortunately after reading all the discrepancies in the timeline I decided to wash it off after 8 hours. I should have washed it off after 4.
      It left a third degree burn on my foot and I also got a skin infection . Do not do this treatment. Go to dermatologist instead.

  19. Avatar Sam says:

    This stuff is the cats meow in my opinion. Yeah, it hurts for a few days. I get treatments on Mondays and can walk mostly normal by Thursday after limping pretty hard Monday evening and Tuesday. Wednesday isn’t the most fun but I’m usually doing better. I’m generally good to go by the weekend and can get back to running and cycling. After two treatments of it the wart has definitely reduced (mind you, this thing was literally the size of a quarter and right on the ball of my foot at the base of the second toe). I had several months of treatments with liquid nitrogen that did absolutely nothing and I would guess I will need 2, maybe 3 more treatments with cantharidin.

  20. Avatar Me says:

    Beetle juice has an extremely painful recovery process. It is mind blowing that my physician and so many others it seems downplays the effects of the blistering. I had to take time off work as I could not walk for 2-3 days at all and was on crutches. Be aware this is a very painful and aggressive treatment. However it is my only hope. This is my second round of it and if it isn’t better, I am giving up as I cannot put myself through the pain again, I have also had laser surgery on the planters wart and it was not even close to being in the same pain scale as the beetlejuice.

  21. Avatar Lindsay says:

    I received treatment on Friday morning. Was told to leave the bandage on as long as possible. Well the bandage finally fell off on Sunday when I took my first shower. I have not had any of the pain at all and nothing has happened so far. Did I do something wrong?? My dr did carve some of it out before he applied the beetle juice

    • WD Staff WD Staff says:

      Hi Lindsay,

      The bandage may fall off after a couple of days, so what you experienced may be typical. However, we would encourage you to contact your provider just to double check. A simple call should suffice!

      WD Staff

  22. Avatar Skylar says:

    I’ve struggled with plantar warts for years. Cryotherapy didn’t work. I had them cut out at the podiatrist but they come back somewhere else. I tried beetle juice and was surprised with the result. It on my pinky toe and didn’t think it was very painful—just a little sore for a few days. I noticed the wart got smaller. 2 months later I picked a piece of dead skin off and saw that the wart was completely gone! I’m going to go back for the rest of my warts. I’m not looking forward to the pain of the next treatment because they’re on the bottom of my feet

  23. Avatar Nora says:

    Is it normal for the wart to grow bigger after this treatment?

    • WD Staff WD Staff says:

      Hi Nora,

      Great question! Sometimes the treated wart can appear to be bigger directly after treatment but that increase in size should not be sustained for a long period. You may want to contact your provider to see if you can be assessed to ensure the treatment is working as intended.

      We hope that helps!

      WD Staff

  24. Avatar Agnes says:

    I’m glad to see that I am not the only person that has experienced extreme pain and mobility issues after this treatment. This is now my 4th treatment and after each one I look at the sites that describe side effects and think I am being a wimp! I have a cluster of plantar warts on the ball of my foot which has been very resistant to resolve. My doctor treated very “aggressively” and the pain was the worst yet. I just hope it ends soon.

  25. Avatar Katie says:

    It’s been 24 hours since Cantharone was applied to the underside of my foot and the pain is so high that no pressure at all can be applied. I am hobbling around the house and honestly do not think I could go about normal activities (getting in a car to go get groceries for example). I am basically only semi comfortable if I am resting or sitting with no pressure on my foot. It even hurts to wriggle my toes. This article does not seem to accurately portray the discomfort of getting this treatment and my dermatologist certainly did not warn me. Thankfully I have no events in the next few days, because there is no way I could put on a high heel or even a slipper and be on my feet. This is something I feel doctors and podiatrists should absolutely warn patients of – be prepared to not be able to walk for a few days.

  26. Avatar Jayleen says:

    I did hear the treatment could be painful but it was one of the only ways left to address the wart. I wonder if pain differs by area. I had this done on my fingers and I found it more uncomfortable than painful. I asked the doc and they said it varies by person, so you might want to discuss this prior to undergoing it.

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