Fasting Before Skin Cancer Surgery (Excision / Mohs)

Fasting for this procedure

For a standard excision or Mohs micrographic surgery, the area is numbed with a local anaesthetic injection while you stay fully awake, so you can normally eat and drink as usual right up to your appointment, and a light meal beforehand is actually a good idea because Mohs can take several hours with waiting between stages. Fasting only becomes necessary if your team has planned sedation or a general anaesthetic, which is more likely for a large reconstruction, a complex skin flap or graft, surgery near the eyes or for very anxious patients. If you are having any sedation or GA, the usual rule applies: stop solid food about 6 hours before arrival and stop clear fluids about 2 hours before. For a child needing sedation or GA, follow the 6-4-2 rule (food and formula 6 hours, breast milk 4 hours, clear fluids 2 hours) and use our child fasting calculator. If you are unsure which type of anaesthetic you are booked for, ring the clinic and ask before the day, because that single answer tells you whether to fast.

Medicines to check

For most small skin excisions under local anaesthetic, blood thinners such as warfarin, apixaban, rivaroxaban or clopidogrel are usually continued, because firm pressure and stitches control the minor bleeding and stopping them carries a higher clot risk. Always confirm with your surgeon first and see medications to stop before surgery.

If you take aspirin, do not stop it on your own. For skin surgery it is very often kept going, but check with the team that booked your operation.

If you have diabetes and are NOT fasting (local anaesthetic), take your tablets and insulin as normal and eat as usual. Only if you are having sedation or GA do the fasting-day rules apply, see diabetes tablets before surgery.

Tell your team about any herbal or over-the-counter supplements such as fish oil, vitamin E, ginkgo or turmeric, as some can increase bruising and oozing around the wound.

Continue your blood pressure, heart, thyroid and other regular medicines as normal unless specifically told otherwise.

Mention any antibiotic allergies or a history of reactions to local anaesthetic, and bring a current list of everything you take.

When this surgery may be delayed

Your blood thinner was stopped when it should not have been, or not stopped when sedation needed it, so the team may rebook to get the timing right and reduce bleeding risk.

You ate or drank within the fasting window for a planned sedation or general anaesthetic, which makes that anaesthetic unsafe on the day.

An active skin infection, cold sore or open infected lesion at or near the surgery site, which is usually treated first so the wound can heal cleanly.

Very high blood pressure or a new chest or heart problem on the day, particularly if sedation or GA was planned for a larger reconstruction.

The lesion turns out to need a larger flap, graft or specialist reconstruction than the booked slot or anaesthetic allows, so it is rescheduled with the right team and time.

Reports & documents to carry

Your appointment letter and any biopsy or pathology result confirming the skin cancer type (for example basal cell, squamous cell or melanoma).

A current list of all your medicines, including blood thinners, insulin, inhalers, herbal remedies and supplements, with doses.

Your anticoagulant or warfarin book and any recent INR result if you take warfarin.

A list of allergies, especially to local anaesthetic, antibiotics, plasters or dressings, plus latex.

If sedation or GA is planned, the name and phone number of the adult driving you home and staying with you, as you must not drive afterwards.

What to ask your anesthesia team

Is my surgery under local anaesthetic only, or sedation or general anaesthetic, so I know whether I need to fast?

Should I keep taking or pause my blood thinner / aspirin before this skin excision, and if pausing, exactly when?

Will I have a simple line of stitches, or a flap or skin graft, and roughly how long should I set aside, especially for Mohs?

How should I care for the wound and stitches at home, can it get wet, and when do the stitches come out?

What bleeding, swelling or signs of infection are normal, and what should prompt me to call you or seek help?

Your prep checklist

Tick things off as you sort them — saved on this device only, nothing is sent anywhere.

A general guide — your hospital's own instructions always come first.

Frequently asked questions

Do I really not need to fast for Mohs surgery?

Usually no. Mohs is done under local anaesthetic while you stay awake, so you can eat and drink normally beforehand. In fact a proper meal is sensible, because Mohs removes the cancer in stages and you may wait a few hours between stages while the tissue is checked under the microscope. Fasting is only needed in the uncommon situation where your team has planned sedation or a general anaesthetic, so always confirm your anaesthetic type first.

Can I keep taking my blood thinner before skin cancer surgery?

For most small excisions under local anaesthetic, yes. Surgeons usually continue warfarin, apixaban, rivaroxaban, clopidogrel and aspirin for skin surgery, because direct pressure and stitches control the minor bleeding, and stopping raises your risk of clots or stroke. There can be exceptions for very large reconstructions or sedation. Never stop a blood thinner on your own, always confirm the exact plan with the surgeon who booked you.

What happens if my excision needs a flap or graft instead of simple stitches?

Larger or deeper cancers sometimes need a skin flap or graft to close the gap and give a good result. These take longer and are more likely to involve sedation or a general anaesthetic, in which case fasting rules do apply: stop solids about 6 hours before and clear fluids about 2 hours before arrival. Ask in advance whether a flap or graft is likely, so you know whether to fast and arrange a driver.

How do I look after the wound and stitches afterwards?

Keep the dressing clean and dry, typically for the first 24 to 48 hours, then follow the specific advice your team gives, as it varies by site and whether you had a flap or graft. Avoid heavy lifting or stretching the area so the stitches are not pulled. Stitches usually come out in about 5 to 14 days depending on location. Contact the team if you see spreading redness, increasing pain, pus or bleeding that will not settle with pressure.