CO2 laser for genital warts and circumcision in Taichung: the facts
This clinic uses an ultra-pulse carbon dioxide laser (CO2 laser) in outpatient procedures. It can cut tissue, as in circumcision, or vaporise small growths such as genital warts.
Explained by Dr. Chao-An Chen, urologist, at 昭安泌尿科診所 (Morning Urology Clinic), West District, Taichung.
In short
- Uses: circumcision for a long foreskin, removal of genital warts, and vaporising other small skin growths (skin tags, polyps, granulation tissue).
- Anaesthesia: mainly local anaesthesia (injection or cream). For warts, sedation by a specialist anaesthesiologist is an option.
- Warts, first treatment: the clinic first takes a tissue sample for pathology, then treats the rest. The report takes about 7 days.
- Warts can come back: often about 20–30% after any treatment, most often in the first 3 months. The laser removes what you can see, not the virus in nearby skin.
- Cost: Costs are explained at the consultation. You can also ask about costs on LINE before you come.
How the laser works, and what the guidelines say
The British BASHH 2024 guideline groups CO2 and Er:YAG lasers as “ablative” lasers: their long-wavelength light is absorbed by the water in tissue, which heats up quickly and is vaporised. “Ultra-pulse” means the energy comes in very short pulses, not as a continuous beam.
For genital warts, the US CDC 2021 guideline counts laser as surgical removal, together with scissor excision, shave excision, curettage (scraping) and electrocautery (burning with an electric current). Each has situations where it fits.
- Anaesthesia first. BASHH 2024 recommends local anaesthesia before laser treatment of warts (grade 1B). CDC 2021 also describes surgical removal after local anaesthesia.
- Smoke safety. Vaporising tissue makes smoke, which may contain HPV particles. BASHH 2024 says a smoke extractor and an N95 or FFP2/FFP3 mask should be used (grade 1A). CDC 2021 asks for a ventilated room with local smoke extraction.
- Heat reaches nearby skin. How wide and how deep depends on the settings and the operator. CDC 2021 warns that the depth of destruction must be controlled to avoid scarring. The doctor adjusts the settings to the type, size and position of the lesion.
- No sample is left. Destroyed or vaporised tissue cannot be sent for pathology (see the next section).
One laser, two kinds of use
Circumcision needs a longer, even cut. Warts and skin growths usually need small, spot treatment. The same CO2 laser can do both by changing its settings; the doctor decides the method and how far to go. The laser can also trim edges and smooth uneven tissue. But the final look, the scar and the speed of healing depend on your skin, the size of the area and your aftercare, and cannot be predicted beforehand.
Biopsy first for warts. The laser turns tissue into vapour, so nothing is left to send to the laboratory. For this reason, at a first laser treatment of warts, the clinic first removes a sample for pathology, then treats the remaining lesions. The report comes back in about 7 days. It confirms the diagnosis and rules out other growths that look similar. If you were treated at another clinic and this is your first visit here, it also counts as a first treatment.
Laser circumcision is one of several circumcision methods. If you have a long foreskin with repeated inflammation, the doctor helps you choose a method and explains recovery at a face-to-face visit. See circumcision options and recovery.
When warts keep coming back
It is common for treated warts to grow again. The European IUSTI 2019 guideline says warts can come back after every type of treatment, often in about 20–30% of people, in the same place or in new places. The longer the follow-up, the higher the figure. The US CDC 2021 guideline says it happens most often in the first 3 months after treatment. The reasons are explained on the genital warts and HPV page (recurrence section).
BASHH 2024 says the evidence is limited. We cannot yet say which treatment makes warts less likely to come back after they clear. For warts that keep returning or will not clear, BASHH recommends laser, electrocautery or surgical excision first (strong recommendation, 1A).
Cream after the laser. BASHH 2024 says applying imiquimod cream for 4–8 weeks after CO2 laser can be considered (weak recommendation, 2A). There is not enough evidence for using it after cryotherapy, electrocautery or other treatments, or for other creams.
Before you start the cream:
- The product information approved in Taiwan says not to use it on ulcerated skin or unhealed wounds, and not after drug or surgical treatment until the wound has healed. So wait until the laser wound heals, then start as prescribed.
- Stop it during pregnancy or breastfeeding.
- Avoid sexual contact while using it. It may weaken condoms and diaphragms, so wash it off before sex.
- CDC 2021: the skin may become red, irritated, hard, broken or form small blisters; lighter skin colour has also been reported. Full instructions follow the Taiwan-approved product information.
If your warts came back, tell us on LINE what treatment you had, how long ago, and where they are now.
Anaesthesia
Local anaesthesia is the main method, by injection or by a numbing cream on the skin. The injection itself hurts. How much pain you feel after the numbness wears off differs from person to person. The doctor prescribes painkillers if needed.
Sedation (intravenous general anaesthesia, IVGA) is an option for wart laser treatment. A specialist anaesthesiologist assesses you and gives it. It is usually booked at a separate time, and you must fast beforehand.
- Weight-loss injections (tirzepatide, semaglutide): always stop them one week before sedation. They slow stomach emptying, so stomach contents are more likely to enter the lungs during anaesthesia. The one-week stop follows the American Society of Anesthesiologists (ASA) 2023 advice. In 2024, several US societies relaxed this: most people can continue, and those at higher risk of stomach side effects take only liquids the day before. This clinic keeps the more cautious one-week stop.
- If you use these medicines for diabetes, ask the prescribing doctor how to control your blood sugar while you stop them.
- Sedation is not free of risk. Fasting rules, limits for the 24 hours after sedation and possible side effects are explained on the sedation risk assessment page (Chinese).
Risks, aftercare and limits
A CO2 laser destroys tissue. Please know these points before and after treatment:
- Suitability. Several kinds of lesion look alike. The doctor confirms at the clinic whether the laser is suitable.
- Aftercare. Keep the wound dry and clean as instructed. Change dressings on time or use the prescribed cream. Avoid getting the wound wet or taking a bath too early, to lower the risk of infection. Come back as booked so the doctor can check healing and, if a sample was sent, explain the pathology report.
- Side effects. Pain, redness, swelling, discharge and bleeding can happen. Infection, colour change (darker or lighter skin) or scarring are also possible. The scar risk is higher if the depth of destruction is not well controlled; the CDC 2021 guideline warns about this.
- Come back early if pain gets worse, bleeding will not stop, the wound has pus, or you have a fever.
- Warts can still return. The laser vaporises the warts you can see. HPV hiding in the nearby skin is not removed, so follow-up visits are needed as advised. The method, the settings and whether it suits you are decided by the doctor at 昭安泌尿科診所 after an examination.
Before you decide
A lump in the genital area is not always a wart. It may be pearly penile papules, sebaceous hyperplasia (overgrown oil glands) or another harmless growth, and each is handled differently. Laser is only one of the treatments listed in the guidelines. The CDC 2021 guideline says there is no clear evidence that any recommended treatment is superior to the others. The choice depends on the size, number and position of the warts, and on the experience of the person treating them.
At the visit, the doctor first checks how wide and how deep the lesions are, then decides the laser settings and whether to add a medicine. If you cannot come in yet, you can describe on LINE where the lesion is, what it looks like, how long you have had it and whether it is spreading.
Frequently asked questions
Will it hurt? Will I need stitches? Will the scar show?
These are the three most common questions, and the answers differ from person to person. The local anaesthetic injection itself hurts, and pain afterwards varies; painkillers are prescribed if needed. The scar and healing depend on your foreskin, the size of the area, your skin and your aftercare, and cannot be predicted beforehand.
My warts came back. Do I need another biopsy?
If pathology at this clinic has already confirmed genital warts, a new wart usually does not need a sample first. If you were treated elsewhere and this is your first visit here, it counts as a first treatment: with the laser, a sample goes to pathology first, and the report takes about 7 days. Bring your past treatment records and pathology report, if you have them.
After the warts are removed, can I still get HPV?
Yes. You can still be infected with other HPV types after treatment. The HPV vaccine is for prevention, not treatment. Because other sexually transmitted infections may come with the same exposure, it is worth checking for them too; see STI screening.
What about freezing (cryotherapy)?
How each treatment works, whether it needs anaesthesia and its main limits are compared in a table on the genital warts and HPV page.
Does laser circumcision help with premature ejaculation?
No. Like other circumcision methods, it is not a treatment for premature ejaculation. The AUA/SMSNA guideline states that ejaculation latency time is not affected by circumcision. If your concern is ejaculating too soon, start with premature ejaculation: types and treatment.
Appointments and access
Consultations are conducted in Mandarin, and can also be conducted in English.
You do not need to explain why you are here in the waiting area; the clinic has private consulting rooms. On LINE, you can describe the lesion in words before you come.
昭安泌尿科診所 (Morning Urology Clinic)
No. 98, Boguan 2nd St., West District, Taichung City 403, Taiwan（403 臺中市西區博館二街98號）
Consulting hours: Monday to Saturday (closed Sunday). Online booking is open 24 hours.
This page was produced by 昭安泌尿科診所 (Morning Urology Clinic). Medical content last updated: October 2026 (same as the Traditional Chinese version). English version published: 5 November 2026. Medically reviewed by Dr. Chao-An Chen, urologist.
Sources: CDC Sexually Transmitted Infections Treatment Guidelines, 2021: Anogenital Warts / BASHH UK national guideline on the management of anogenital warts (2024) / IUSTI-Europe guideline for the management of anogenital warts (2019) / American Society of Anesthesiologists (ASA) 2023 advice / AUA/SMSNA guideline / Taiwan-approved product information for imiquimod.
This page provides general medical information and does not replace an individual diagnosis or treatment plan.