As this is published I am finishing the last day of a 12 day stretch covering my partner while he is off trying to get MDRTB and typhoid fever.  He is in India. I may have to autoclave him when he returns before I let him in the hospital.  Double the work means double the fun, but free time goes down by the power.  Same thing happens with the kids.  If you have two kids, the work squares, three kids, the work cubes.  A linear change in one domain leads to exponential change in other domains.  I am sure that phenomena has a name that one of our readers will know.

I lack the mad typing skills of other contributors and it usually takes me at least a week to carefully construct the spelling errors and grammatical faux paux for which I am justly famous.  And then I have to come up with content to surround the faulty English.  This week I have little time and so a ‘fun’ post.

When I make rounds it is not unusual for people to ask questions about their health and their family.  I learned long ago to ask why they want an answer to a particular question so I do not inadvertently offend a colleague.  When I offend I like to be advertent.  Years ago I was asked what I thought of hyperbaric oxygen, and I replied that it is great for the bends but otherwise mostly serves to enrich the hyperbaric doctors.  Why do you ask?  I am the new director of the hyperbaric program, was the reply.  Open mouth and insert foot.

So recently a nurse asked me if duct tape would remove warts.  Wary, I asked why, and she showed me a huge wart on her hand.  I have used duct tape for many purposes; few home repairs cannot be (temporarily) accomplished with duct tape. But treating warts?  Do you use the tape as a way to yank the wart out by its roots?  Got me.  I gave my best Gallic shrug and went looking for information.

Warts, and from here on I am referring to common warts on the hand, are due to a virus, the papilloma virus.  Or so I was taught.  For the first two years I took the bus to medical school and occasionally someone would see I was reading a medical text and strike up a conversation.  This usually occurred on the trip to school.  After gross anatomy lab, the last class of the day, I usually sat alone, I assume the  result of my smell.  Preserved cadavers have a penetrating fragrance that saturates the skin and hair and will drive away even urine stained crazies.

Once it was a student at the naturopathic school who noted that, contrary to what I was taught, warts are actually the result of the body walling off toxins and expelling them.  I remember thinking at time, this is a loon, and the last thing you do is egg-on a loon when you can’t run away.  So I smiled grimly, made non-committal grunts and was relieved when he got off the bus.  Turns out he wasn’t a loon, but was repeating the teaching of his school.  It is the school that has the loons.

Naturopaths believe that such symptoms as warts are the result of toxins in the body, and an immune system that is not running efficiently. They may prescribe treatments such as colonic irrigation, alongside a program of healthy eating to raise the general level of health. A naturopath may suggest a paste made with vitamin C, applied to the wart daily for a period of a few weeks.

Remember, these folks want to be primary care docs: have a wart, get a colonic.

Determining effective treatments for warts is problematic since the natural history for warts is to go away.  In a study that is slightly creepy, but how it was done back in the day, they found:

The natural history of warts was recorded by examining 1,000 institutionalized mentally defective children for 2 years. Treatment of warts was withheld. We found: (1) The overall incidence increased from 18% to 25% in 2 years. (2) The dynamic aspect of warts was reflected by the fact that two-thirds of the original lesions in 168 cases involuted within 2 years. (3) Involution occurred almost twice as often in boys as girls.

That is the only study of the natural history of warts I can find.  2/3 will go away in two years.  So if you get two years of colonics you can credit the colonic with the resolution of the warts.

And the Cochrane reviews notes

In 21 trials with placebo groups that used participants as the unit of analysis, the average cure rate of placebo preparations was 27% (range 0 to 73%) after an average period of 15 weeks (range 4 to 24 weeks).

Warts are a self-limited disease.

There are many popular remedies for warts.  Pick a SCAM, it has been used on warts.  Some allege benefit, some do not.  My wife, who grew up in rural Minnesota, swears by milkweed.  She is anecdote central for the efficacy of milkweed.  Warts melt away with application of the milkweed milk.  There was one clinical trial out of India that evaluated milkweed and  it did not work.

There are over 140 types of milkweed, and in Minnesota it is Asclepias syriaca, not the Asclepius curussavica tested in India, so the best you can say is one down, 139 to go.  Besides, I am not going to cross my wife on the efficacy of milkweed, although I would on vaccines if needed.

Of the popular cures for warts my favorites are from Mark Twain:

Aha! Talk about trying to cure warts with spunk-water such a blame fool way as that! Why, that ain’t a-going to do any good. You got to go all by yourself, to the middle of the woods, where you know there’s a spunk-water stump, and just as it’s midnight you back up against the stump and jam your hand in and say:

‘Barley-corn, barley-corn, injun-meal shorts,
Spunk-water, spunk-water, swaller these warts,’
and then walk away quick, eleven steps, with your eyes shut, and then turn around three times and walk home without speaking to anybody. Because if you speak the charm’s busted.”
“Well, that sounds like a good way; but that ain’t the way Bob Tanner done.”

“No, sir, you can bet he didn’t, becuz he’s the wartiest boy in this town; and he wouldn’t have a wart on him if he’d knowed how to work spunk-water. I’ve took off thousands of warts off of my hands that way, Huck. I play with frogs so much that I’ve always got considerable many warts. Sometimes I take ’em off with a bean.”

“Yes, bean’s good. I’ve done that.”

“Have you? What’s your way?”

“You take and split the bean, and cut the wart so as to get some blood, and then you put the blood on one piece of the bean and take and dig a hole and bury it ’bout midnight at the crossroads in the dark of the moon, and then you burn up the rest of the bean. You see that piece that’s got the blood on it will keep drawing and drawing, trying to fetch the other piece to it, and so that helps the blood to draw the wart, and pretty soon off she comes.”

“Yes, that’s it, Huck — that’s it; though when you’re burying it if you say ‘Down bean; off wart; come no more to bother me!’ it’s better. That’s the way Joe Harper does, and he’s been nearly to Coonville and most everywheres. But say — how do you cure ’em with dead cats?”

“Why, you take your cat and go and get in the graveyard ‘long about midnight when somebody that was wicked has been buried; and when it’s midnight a devil will come, or maybe two or three, but you can’t see ’em, you can only hear something like the wind, or maybe hear ’em talk; and when they’re taking that feller away, you heave your cat after ’em and say, ‘Devil follow corpse, cat follow devil, warts follow cat, I’m done with ye!’ That’ll fetch any wart.”

Although the final cure does run risk of witnessing a murder and all the adventures that follow.

There is an interesting and variable literature on hypnosis curing warts that someday I would like to review but I know so little about hypnosis and this is not the time or place.  Warts have a more supernatural/mind-body reputation to their treatment than most common ailments.  Although I had always been told that people could hypnotize away warts on one side of the body only, what literature I could find suggests it is not true.  Bummer.  One of my favorite myths.  I will feel the need to start a sentence with actually next time the topic comes up.

I received an interesting email from a colleague, Dr. Robinson, with this approach to warts:

Burkhart freezes them first. Then he adds a yeast extract and several liquids, including the juice from a Asian blistering beetle – not sold in the United States.

But here, Burkhart plumbs the darker methodology. At 33, dressed in a bow tie, the Chapel Hill physician hardly looks the part of wart shaman. Spend 20 minutes in his Southern Village office, and you get the feeling he could smile the warts off your finger.

He’s eradicated more than 100 of the little devils, mostly from children. He’s tackled the common sort that pop up around the eyes, the stubborn variety that sprout around fingernails and, once, an irritating growth from a football player’s foot.

But he’s willing to dive into weird practices, or at least the pages of long-forgotten Advanced Dermatology Therapy, published in 1987 by fellow Toledo native Dr. Walter B. Shelley.

Borrowing the late Shelley’s technique, Burkhart wraps the offending growth in silk tape and asks the patient to describe its mood. Angry wart? He draws an angry face on the bandage. Sad wart? He draws a sad face. Next, he offers the patient an exotic coin. He carries them in a Ziploc bag: Norwegian kroner and Argentine pesos. One coin equals the price of one wart. If the growth returns, he expects his coin back. But so far, after probably 100 wart exorcisms, he’s never needed a refund.

Finally, he tells patients to remove the bandage at the stroke of midnight. If that’s too late for a patient, he offers bedtime as a substitute.

I get the feeling that Burkhart is having fun with the wart therapy, since he is treating children, and it is part of the art of medicine that I can appreciate and admire.  But it still has the odd vibe that hypnosis adds to wart therapy.

I have to stay on topic.  The topic is duct tape.  Squirrel.

There are a surprising number of hits when searching the topic on PubMed.

The mechanism by which duct tape is alleged to work is the Goldfinger effect: by occluding the area it is denied oxygen and dies.  Warts are supplied from the inside, as are people, and neither warts nor Jill Masterson will die as a result of being covered with duct tape or paint.

There are clinical trials for duct tape.  Duct tape does not work in adults:

There were no statistically significant differences in the proportions of patients with resolution of the target wart (8 [21%] of 39 patients in the treatment group vs 9 [22%] of 41 in the control group). Of patients with complete resolution, 6 (75%) in the treatment group and 3 (33%) in the control group had recurrence of the target wart by the sixth month.

But warts are usually more difficult to treat in adults, so how about kids? Nope.

Duct tape applied to the wart or placebo, a corn pad (protection ring for clavi), applied around the wart for 1 night a week. Both treatments were applied for a period of 6 weeks. Patients were blinded to the hypothesis of the study.
Complete resolution of the treated wart.
After 6 weeks, the wart had disappeared in 16% of the children in the duct tape group compared with 6% in the placebo group (P = .12). The estimated effect of duct tape compared with placebo on diameter reduction of the treated wart was 1.0 mm (P = .02, 95% confidence interval, -1.7 to -0.1). After 6 weeks, in 7 children (21%) in the duct tape group, a surrounding wart had disappeared compared with 9 children (27%) in the placebo group (P = .79). Fifteen percent of the children in the duct tape group reported adverse effects such as erythema, eczema, and wounds compared with 0 in the placebo group (P = .14).
In a 6-week trial, duct tape had a modest but nonsignificant effect on wart resolution and diameter reduction when compared with placebo in a cohort of primary school children.

At least no better than placebo, but better than cryotherapy:

Patients were randomized using computer-generated codes to receive either cryotherapy (liquid nitrogen applied to each wart for 10 seconds every 2-3 weeks) for a maximum of 6 treatments or duct tape occlusion (applied directly to the wart) for a maximum of 2 months. Patients had their warts measured at baseline and with return visits.
Complete resolution of the wart being studied.
Of the 51 patients completing the study, 26 (51%) were treated with duct tape, and 25 (49%) were treated with cryotherapy. Twenty-two patients (85%) in the duct tape arm vs 15 patients (60%) enrolled in the cryotherapy arm had complete resolution of their warts (P =.05 by chi(2) analysis). The majority of warts that responded to either therapy did so within the first month of treatment.
Duct tape occlusion therapy was significantly more effective than cryotherapy for treatment of the common wart.

Although when you read the wart treatment literature there is great variability in all the responses to all the therapies depending in part how long you follow them.

The Cochrane reviews only found two duct tape studies, as did I, and suggest that most therapies for warts are of minimal efficacy over doing nothing.  Systematic reviews suggest that best therapy is not still known for warts.

Overall, trials comparing cryotherapy with placebo showed no significant difference in effectiveness, but the same was also true for trials comparing cryotherapy with [salicylic acid]. Only one trial showed cryotherapy to be better than both SA and placebo, and this was only for hand warts. Adverse effects, such as pain, blistering, and scarring, were not consistently reported but are probably more common with cryotherapy. None of the other reviewed treatments appeared safer or more effective than SA and cryotherapy. Two trials of clear duct tape demonstrated no advantage over placebo.

It appears duct tape does nothing and other therapies little more.  Me?  I’m sticking with the dead cat in the cemetery.  Anything that involves a dead cat is good by definition.



  • Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at

Posted by Mark Crislip

Mark Crislip, MD has been a practicing Infectious Disease specialist in Portland, Oregon, from 1990 to 2023. He has been voted a US News and World Report best US doctor, best ID doctor in Portland Magazine multiple times, has multiple teaching awards and, most importantly,  the ‘Attending Most Likely To Tell It Like It Is’ by the medical residents at his hospital. His multi-media empire can be found at