Cantharidin: uses, dosing, side effects & brands
Cantharidin is a medicine sold in the U.S. under one brand, for molluscum contagiosum and warts. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Treats
- Molluscum Contagiosum and Warts
- Available as
- Solution
- Sold as
- Ycanth
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How cantharidin is dosed
From the FDA label for Ycanth (application NDA212905). Other cantharidin products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
All healthcare professionals should receive instruction and training prior to preparation and administration of YCANTH. ( 2.1 ) For topical use only. Not for oral, mucosal, or ophthalmic use. ( 2.1 ) Apply a single application directly to each lesion every 3 weeks as needed. ( 2.2 ) Do not use more than two applicators during a single treatment session. ( 2.2 ) Remove with soap and water 24 hours after treatment. ( 2.2 ) For additional instructions on preparation and administration of YCANTH, see Full Prescribing Information. ( 2.1 , 2.2 , 2.3 ) 2.1 Important Administration Instructions All healthcare professionals should receive instruction and training prior to preparation and administration of YCANTH. YCANTH is for topical use only. YCANTH is not for oral, mucosal, or ophthalmic use. Avoid contact with the treatment area, including oral contact, after YCANTH treatment. Do not apply YCANTH near the eyes [see Warnings and Precautions (5.1) , Overdosage (10) ] . If YCANTH contacts any unintended surface, including healthy skin, immediately remove by wiping with a cotton swab or gauze. Avoid other topical products on treated areas until 24 hours after YCANTH treatment or until washing [see Warnings and Precautions (5.2) ]. Avoid fire, flame or smoking near lesion(s) during treatment [see Warnings and Precautions (5.3) ] . 2.2 Dosage and Administration Overview Regarding YCANTH…
Cantharidin side effects
The following adverse reactions are described elsewhere in the labeling: Local Skin Reactions [see Warnings and Precautions (5.2) ] Most common (incidence ≥1%) adverse reactions are the following local skin reactions at the application site: vesiculation, pain, pruritus, scabbing, erythema, discoloration, application site dryness, edema, and erosion. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Verrica Pharmaceuticals Inc. at 1-877-837-7422 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Local skin reactions are expected and should be reported if they are severe. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. YCANTH was studied in two randomized, double-blind, placebo-controlled phase 3 trials, Trial 1 (NCT03377790) and Trial 2 (NCT03377803) (n = 266, and n = 262, respectively) in subjects with molluscum contagiosum. Most patients received a single 24-hour dermal administration of YCANTH or vehicle for each lesion every 3 weeks for up to 4 treatments. YCANTH Solution or vehicle were removed prior to the 24-hour timepoint in 109/311 (35%) subjects treated with YCANTH Solution and 46/216 (21%) subjects treated with vehicle…
Who shouldn’t take cantharidin
None None
Every cantharidin product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Ycanth.
Can you crush or split cantharidin?
At least one cantharidinproduct is labelled to be swallowed whole — crushing an extended-release tablet releases the whole day’s dose at once. Which applies depends on the form you were given.
What each cantharidin label says about crushing, splitting and chewingWhat people report to the FDA about cantharidin
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 28 reports naming cantharidin, and the FDA flagged 64% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- application site vesicles6 reports
- acute kidney injury3 reports
- application site pain3 reports
- application site erythema2 reports
- drug resistance2 reports
- hypercholesterolaemia2 reports
- hyperuricaemia2 reports
- multiple-drug resistance2 reports
Read these as a signal, not a rate. A report does not mean cantharidin caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
Related calculators
Frequently asked questions
What is cantharidin?
YCANTH (cantharidin) topical solution is a light violet to dark purple, slightly viscous liquid for topical administration. Each mL of YCANTH topical solution contains 7 mg of active ingredient cantharidin (0.7%), a lipophilic compound. Cantharidin is a white to off-white solid at room temperature and is only very slightly soluble in water.
Can you take cantharidin with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run cantharidin against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does cantharidin come in?
Across the brands we track, cantharidin is currently marketed as solution, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic cantharidin?
We do not currently list a generic-labelled cantharidin product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Cantharidin: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/cantharidin
- MLA
- “Cantharidin: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/cantharidin.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for cantharidin on DailyMed (NIH) ↗.