Argon plasma coagulation
A treatment done during an endoscopy that uses argon gas and an electric current to deliver heat without touching the tissue, mainly to stop or prevent bleeding from fragile blood vessels in the gut.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- APC uses argon gas and an electric current to deliver heat without touching the tissue, mainly to stop or prevent bleeding from fragile blood vessels in the gut.
- It treats the surface it is applied to but does not cure the underlying cause, so conditions such as GAVE or angiodysplasia often need several sessions and can recur.
- It is carried out during a gastroscopy or colonoscopy, usually with throat spray or sedation; if you have sedation you cannot drive for 24 hours and need an escort.
- Because it uses heat, there is a small but real risk of bleeding or a tear (perforation) of the gut, which is higher than for a plain camera test.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Can stop or reduce bleeding from fragile blood vessels in the gut
APC treats the surface, so it is not a cure for the underlying cause of bleeding vessels, which can recur.
You rest while sedation wears off or throat numbness settles. If you had throat spray, you must not eat or drink until the numbness has gone (usually...
Clear written warning signs (bleeding, black stools, severe pain, fever) and exactly what to do.
You rest while sedation wears off or throat numbness settles. If you had throat spray, you must not eat or drink...
You can eat and drink once any throat numbness has worn off. If you had sedation, go home with a responsible...
A mild sore throat, bloating or tummy cramps usually settle. There may be a small amount of bleeding from the...
The effect on bleeding or anaemia is judged over time, often with blood tests. Because the problem can recur, a...
What is argon plasma coagulation?
Argon plasma coagulation, or APC, is a treatment carried out during an endoscopy — a gastroscopy for the gullet and stomach, or a colonoscopy for the bowel. A thin probe is passed through the endoscope, and argon gas is used to carry an electric current to the tissue as a fine spray, delivering heat without the probe needing to touch the surface. This seals small blood vessels and treats a thin layer of the lining.
It is used most often to stop or prevent bleeding from fragile, abnormal blood vessels in the gut, such as angiodysplasia or gastric antral vascular ectasia (GAVE, sometimes called 'watermelon stomach'). It can also be used to treat small areas of abnormal lining, to remove residual tissue after a polyp has been taken off, and in some cases to treat Barrett's oesophagus.
APC treats the surface it is applied to; it does not cure the underlying tendency to form these vessels or changes, so the problem can recur and several sessions are often needed. It does not look at the rest of the gut or treat conditions elsewhere. The treatment adds only a little to the endoscopy itself, and the experience is much like having a gastroscopy or colonoscopy, with the choice of throat spray or sedation for upper-gut treatment.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
APC for bleeding blood vessels (angiodysplasia)
Sealing small, fragile abnormal vessels in the gut that cause bleeding or anaemia. Often the main reason APC is used, and frequently needs more than one session.
APC for GAVE ('watermelon stomach')
Treating the streaky, fragile vessels in the lower stomach that cause GAVE. It is an established treatment but often needs repeated sessions because GAVE tends to recur.
APC for Barrett's oesophagus
Used in selected cases to treat abnormal lining in the gullet, often over several sessions. Other techniques are also used, and your team will advise which is most...
APC after polyp removal
Treating any small amount of tissue left at the edges after a polyp has been removed, to reduce the chance of it growing back. The area may be marked with ink for follow-up.
Preparing for your procedure
- Follow the unit's fasting instructions for the relevant test — usually no food for several hours, and for a colonoscopy a bowel-cleansing preparation beforehand.
- Tell the team about all your medicines, especially blood thinners, and ask which to stop or adjust and when.
- Mention any heart device, such as a pacemaker, as the electric current used means this needs to be checked beforehand.
- Mention heart, lung or kidney conditions, sleep apnoea, or any reaction to sedation, as these affect your sedation choice and monitoring.
- Decide whether you would prefer throat spray or sedation for upper-gut treatment, and discuss the pros and cons.
- If you choose sedation, arrange for a responsible adult to take you home and stay with you, and do not plan to drive or work for 24 hours.
- Ask how many sessions you are likely to need, as APC is often repeated.
- Know the warning signs to watch for after the procedure before you leave.
What happens
APC is carried out during a gastroscopy or a colonoscopy. After your details and consent are checked, you have either a numbing throat spray or sedation through a small cannula, depending on the test and your choice. A clip on your finger monitors your pulse and oxygen, and for a gastroscopy a mouth guard protects your teeth and the camera.
The endoscopist passes the flexible camera to the area being treated. A thin APC probe is then passed through the endoscope, and argon gas carries an electric current to the tissue as a fine spray, delivering heat just above the surface without the probe touching it. The treated lining turns pale or whitish as the small vessels are sealed. You should not feel the heat itself, though you may feel some bloating from the gas used to open up the view. Several areas may be treated in one session.
The treatment usually adds only a short time to the endoscopy. Afterwards you rest until any sedation wears off or the throat numbness settles. Because conditions such as GAVE and angiodysplasia tend to recur, APC is often repeated over several sessions, and the endoscopist may mark a treated area with ink so it can be checked at follow-up.
Is this procedure right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- APC treats the surface, so it is not a cure for the underlying cause of bleeding vessels, which can recur.
- It is not suitable for deep or large lesions that need a different technique, such as removal or surgery.
- It may not be appropriate when bleeding is from a source better treated another way, such as varices.
- People who are too unwell or unstable for the endoscopy may need other measures first.
Delay or rearrange if…
- You have not been able to fast, or to complete bowel preparation for a colonoscopy.
- Your blood thinners have not been planned around the procedure.
- A pacemaker or heart device has not yet been checked, given the electric current used.
- You have an active chest infection or are acutely unwell, unless the procedure is urgent.
- You cannot arrange a responsible adult to take you home if you choose sedation.
Alternatives to discuss
- Other endoscopic treatments to stop bleeding, such as clips, heat probes or injection.
- Endoscopic band ligation, which is sometimes used for GAVE.
- Iron treatment or transfusion to manage anaemia, alongside or instead of repeated treatment.
- Medicines or, in selected cases, surgery for the underlying condition.
- Watchful waiting with monitoring if bleeding is minor and not causing problems.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Comfort, sedation or contrast choices
If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.
Benefits
- Can stop or reduce bleeding from fragile blood vessels in the gut
- Can improve anaemia caused by ongoing slow bleeding from these vessels
- Is an established, targeted treatment for conditions such as GAVE and angiodysplasia
- Can treat residual tissue after polyp removal, reducing the chance of regrowth
- Is carried out during an endoscopy without the need for an operation
- Can be repeated over several sessions as needed
Risks & complications
- A sore or scratchy throat after a gastroscopy, or bloating and wind from the gas used
- Feeling tired or groggy for the rest of the day if you have sedation
- Mild tummy discomfort or cramping after treatment, especially in the bowel
- The need for more than one session, as the problem often recurs
- A small amount of bleeding from the treated area
- Breathing, heart-rate or blood-pressure effects from sedation that need monitoring
- An incomplete result, with bleeding or symptoms continuing and needing repeat treatment
- An ulcer or sore area forming where the lining was treated
- A tear (perforation) of the gut, which can need urgent treatment or an operation
- Significant bleeding needing further treatment, admission or a transfusion
- A build-up of gas in the wall of the gut, which usually settles but occasionally needs attention
- A serious reaction to sedation, or breathing stomach contents into the lungs
- Rarely, damage to surrounding tissue or, in the bowel, a delayed perforation
APC is a targeted treatment, but because it uses heat, the risk of bleeding or a tear (perforation) is higher than for a plain camera test, though still uncommon. The risk is greater for treatment in the bowel, especially for larger areas or polyps on the right side of the colon. The other key point is that APC treats the surface, not the underlying cause, so conditions such as GAVE and angiodysplasia often recur and need repeated sessions. Tell the team about any pacemaker or heart device, as the electric current needs to be managed. Ask how many sessions you are likely to need, what to do if you have bleeding or severe pain afterwards, and how a complication would be handled.
Published figures to discuss
APC is an established, targeted treatment, but because it uses heat, the risk of bleeding or perforation is higher than for a plain camera test, though still uncommon, and is greatest for treatment in the bowel, particularly larger areas or polyps on the right side of the colon. Its effectiveness varies by condition: bleeding from GAVE and angiodysplasia is often controlled but commonly recurs, so several sessions are usual. Published figures come from individual studies and units, so the ranges below are cautious and source-defensible rather than exact.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Perforation or bleeding (bowel/colonoscopy) | Uncommon — one NHS leaflet quotes roughly 1–2% for procedures using APC in the colon | Highest when treating larger areas or removing large polyps on the right side of the colon; may need urgent treatment or an operation. | Royal Berkshire NHS — Argon plasma coagulation (APC) patient leafletroyalberkshire.nhs.ukPublished figure |
| Recurrence of GAVE or angiodysplasia | Common — many people need repeated sessions, with recurrence often reported around 30–60% in studies of GAVE | Reflects that APC treats the surface, not the underlying cause; ongoing follow-up and blood tests for anaemia are usual. | APC for upper GI angiodysplasia and GAVE haemorrhage — PMCpmc.ncbi.nlm.nih.govPublished figure |
| Sore throat, bloating or cramps | Common — affects many people for a day or two | Expected after-effects of the endoscopy rather than complications; usually settle on their own. | APC for upper GI angiodysplasia and GAVE haemorrhage — PMCpmc.ncbi.nlm.nih.govSource-linked context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
Recovery is much like that after a gastroscopy or colonoscopy. Most people feel back to normal by the next day, with no wound to heal, though you may have a sore throat, bloating or mild cramps, and if you had sedation you must take it easy and not drive for 24 hours. The effect on bleeding or symptoms is judged over the following weeks.
- A mild sore or scratchy throat for a day or two after a gastroscopy
- Bloating, wind or mild cramps that ease as trapped gas passes
- Feeling tired or 'not quite yourself' for the rest of the day after sedation
- A small amount of bleeding from the treated area in some people
- Knowing that further sessions may be needed as the problem can recur
Aftercare
- If you had throat spray, do not eat or drink until the numbness has fully worn off (about an hour) to avoid choking.
- Start with light food and plenty of fluids, and eat normally as any discomfort settles.
- If you had sedation, have a responsible adult with you and do not drive, operate machinery, drink alcohol or make important decisions for 24 hours.
- Rest for the remainder of the day and resume normal activities the next day if you feel well.
- Restart any medicines, including blood thinners, only as your team advised.
- Keep any planned blood tests to check for anaemia, and attend any follow-up or repeat session.
- Keep the unit's contact number to hand and know the warning signs to report.
- Note when and how you will hear about results or the plan for further treatment.
- Fasting (and bowel preparation for a colonoscopy) instructions understood
- Blood thinners discussed and a plan agreed
- Any pacemaker or heart device flagged and checked beforehand
- Sedation or throat-spray choice decided
- A responsible adult to take you home and stay 24 hours if you choose sedation
- Warning signs (bleeding, severe pain, fever) clearly understood
- The unit's contact number saved
- A clear plan for blood tests, results and any repeat session
⚠ Get urgent help if…
- Severe or worsening tummy, chest or throat pain after the procedure
- Vomiting blood, or bringing up material that looks like coffee grounds
- Black, tarry stools, or a significant amount of fresh blood from the back passage
- A swollen, hard or very tender tummy
- Difficulty or pain on breathing, or new shortness of breath
- A high temperature, chills or feeling very unwell
- Feeling faint, dizzy or very weak
- Any of these — contact the unit or seek urgent care, as a tear or bleed needs prompt treatment
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
When APC works well, bleeding from fragile vessels is reduced or stopped, anaemia can improve, and treated areas of abnormal lining are cleared. The endoscopist can usually describe what was treated on the day, while the effect on bleeding or anaemia is judged over the following weeks, often with blood tests.
It is important to be realistic: APC treats the surface it is applied to, not the underlying tendency to form these vessels or changes. Conditions such as GAVE and angiodysplasia commonly recur, so several sessions are often needed and follow-up matters. APC does not look at or treat problems elsewhere in the gut, and a treated area may need rechecking. Your team should explain what APC can achieve for you and how many sessions are likely.
How long the benefit lasts depends on the condition being treated. For one-off bleeding points, a single treatment may be enough. For conditions such as GAVE or widespread angiodysplasia, the problem commonly recurs, so repeated sessions and ongoing follow-up — including blood tests for anaemia and sometimes repeat endoscopies — are usual. APC controls the problem rather than removing the underlying cause.
Related tests, treatments or support
APC is carried out during a gastroscopy or colonoscopy and may be combined with other endoscopic treatments in the same session, such as removing a polyp or other ways of stopping bleeding. People are often having blood tests for anaemia, iron treatment, and management of any underlying condition at the same time. Where APC is used for Barrett's oesophagus or after polyp removal, it forms part of a wider surveillance plan. Your team should explain how these fit together.
Follow-up & long-term care
The endoscopist can usually tell you what was treated on the day. You should be told how the effect on bleeding or anaemia will be checked — often with blood tests — and whether and when a repeat session or follow-up endoscopy is planned, as recurrence is common. You should also be told who to contact, and exactly what to do, if you have any warning signs such as bleeding or severe pain afterwards.
- Attend any planned repeat APC sessions, as conditions such as GAVE and angiodysplasia often recur.
- Keep up blood tests to monitor for anaemia and take any iron treatment as prescribed.
- Attend follow-up endoscopies to check treated areas, including any marked with ink.
- Take and adjust medicines, including blood thinners, only as your team advises.
- Report new or returning bleeding promptly rather than waiting.
- Follow the wider plan for any underlying condition.
Repeat, follow-on and what comes next
- APC is frequently repeated over several sessions, especially for GAVE and widespread angiodysplasia.
- A treated area may be marked with ink so it can be checked at a follow-up endoscopy.
- Continuing bleeding or anaemia may prompt further APC or a different treatment.
- Recurrence is common because the underlying cause is not removed, so follow-up matters.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- Clear written warning signs (bleeding, black stools, severe pain, fever) and exactly what to do.
- A defined plan for blood tests to monitor anaemia and for any repeat sessions.
- Follow-up endoscopy to check treated areas, including any marked with ink.
- Coordination with the wider team managing any underlying condition.
- A named contact or unit number for problems at home.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The endoscopist's fee and the endoscopy unit or hospital facility fee
- Whether it is done during a gastroscopy or a colonoscopy
- Whether sedation is used and the level of monitoring needed
- The number of sessions required, as APC is often repeated
- Any blood tests to monitor anaemia and any iron treatment
- Follow-up endoscopies to check treated areas or treat recurrence
- Management of the underlying condition, charged separately
- The endoscopist's fee and the unit or hospital facility fee
- Whether it is part of a gastroscopy or colonoscopy, and how that is charged
- Sedation and monitoring costs, or whether throat spray is used
- How many sessions are expected and whether each is charged separately
- Whether follow-up endoscopies and blood tests are included
- What happens, and who is responsible, if a complication such as bleeding or perforation occurs
- The cancellation and rebooking policy
On the NHS? Argon plasma coagulation is carried out on the NHS when clinically indicated, for example for bleeding vessels or GAVE; it may also be done privately, but it is performed during a gastroscopy or colonoscopy.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not explaining that APC treats the surface and that conditions such as GAVE commonly recur and need repeat sessions.
- Not warning that, because it uses heat, the risk of bleeding or perforation is higher than for a plain camera test.
- Not asking about a pacemaker or heart device before using the electric current.
- Not discussing throat spray versus sedation and the 24-hour driving and escort rules.
- No clear warning-sign advice or emergency contact for bleeding or severe pain at home.
Marketing red flags
- Describing APC as a one-off 'cure' rather than a treatment that often needs repeating.
- Downplaying the heat-related risk of bleeding or perforation.
- Not mentioning the need for follow-up and monitoring for anaemia.
- Offering APC without a clear plan for the underlying condition.
- No clear arrangement for managing a complication out of hours.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- What condition is the APC treating, and what is it aiming to achieve?
- How many sessions am I likely to need, and how will recurrence be checked?
- How should I manage my blood thinners around the procedure?
- I have a pacemaker or heart device — how will this be managed?
- Exactly what should I do, and who should I contact, if I have bleeding or severe pain afterwards?
- How will the effect on my bleeding or anaemia be monitored, and when will I hear about results?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my procedure, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this procedure not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
What is APC used for?
Does APC hurt?
Will I need more than one session?
What are the main risks?
I have a pacemaker — does that matter?
Is APC available on the NHS?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: Royal Berkshire NHS — Argon plasma coagulation (APC) patient leaflet University Hospital Southampton — Colonoscopy: argon plasma coagulation (patient factsheet) APC for upper GI angiodysplasia and GAVE haemorrhage — PMC APC therapy for ablation of Barrett's oesophagus — PMC British Society of Gastroenterology — clinical resources
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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