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Fistulotomy smell: is it normal?

Published 13 March 2026 ·Last reviewed 13 March 2026 by the editorial team ·How we create our content

At a glance

Wound odour after fistulotomy is one of the most common concerns people have during recovery — and one of the least discussed. The wound is left open to heal from the inside out, it is in close proximity to the bowel, and it produces drainage. Some smell is expected. But knowing the difference between normal healing odour and a sign of infection is important.

Why fistulotomy wounds have an odour

Several factors contribute:

  • Location — the wound is near the anal area, where bacteria are naturally present
  • Open wound healing — the wound is not stitched closed, so it is exposed to the environment
  • Drainage — wound fluid (serous or serosanguinous) has a natural mild odour
  • Gauze and packing — wound packing that sits in a warm, moist environment can develop an odour between changes
  • Proximity to bowel movements — even with careful cleaning, small amounts of stool can contact the wound area

Normal versus concerning odour

Normal

  • A mild, slightly musty or wound-like smell
  • Odour that is most noticeable when changing gauze or packing
  • Smell that reduces after cleaning or a sitz bath
  • Consistent — not suddenly changing or worsening
  • Not accompanied by fever, increasing pain, or dramatic changes in discharge

Potentially concerning

  • A distinctly foul or putrid smell — different from the baseline wound odour
  • Odour that is getting worse over days
  • Accompanied by green or yellow discharge that is increasing
  • Accompanied by fever, chills, or feeling generally unwell
  • Accompanied by increasing pain or redness around the wound
  • A sudden change in smell character

Managing wound odour

Keep the wound clean

  • Sitz baths after every bowel movement — warm water, no additives needed
  • Additional sitz baths or gentle showers one to two times daily
  • Pat dry thoroughly — moisture promotes bacterial growth

Change dressings regularly

  • Gauze or wound packing should be changed at least once or twice daily, and after any bowel movement
  • Damp gauze left in place for extended periods will develop more odour
  • Use clean, fresh gauze each time

Wound care basics

  • No soap, antiseptic, or fragranced products in or near the wound
  • Warm water only for cleaning
  • Let the wound air dry when possible — after a sitz bath, before applying fresh gauze
  • Wear loose, breathable underwear

Practical tips for managing odour in daily life

  • Keep spare gauze and underwear with you when out
  • Change gauze before social situations
  • Dark underwear reduces anxiety about visible drainage
  • A small, discreet bag with supplies makes workplace or travel management easier

When to contact your surgical team

Contact your surgical team or GP if:

  • The smell is distinctly foul and getting worse
  • You develop a fever (temperature above 38 degrees C)
  • Pain is increasing rather than gradually decreasing
  • Discharge becomes thick, green, or significantly increased in amount
  • Redness is spreading around the wound
  • You are concerned — wound assessment is a routine part of post-operative care, and your team expects these calls

Common questions

Is it normal for a fistulotomy wound to smell?

Some degree of odour from a healing fistulotomy wound is common and usually normal. The wound is in an area near the bowel, it is healing by secondary intention (open), and there is drainage. A mild wound odour that is not accompanied by fever, increasing pain, or worsening discharge is typically part of normal healing.

When does the smell indicate a problem?

A significantly foul, worsening, or newly different smell — particularly if accompanied by fever, increased pain, swelling, redness, or a change in the colour of the discharge — may indicate infection. Contact your surgical team if you notice this combination of changes.

How can I manage the odour?

Regular sitz baths keep the wound clean and reduce odour. Changing gauze pads frequently helps. Keeping the area dry between changes reduces bacterial growth. Some people find that showering the area with warm water two to three times a day makes a significant difference.

How long does the smell last?

Mild wound odour typically reduces as the wound heals and drainage decreases. For most people, the noticeable smell has largely resolved by three to six weeks, though this depends on the size and depth of the wound.

When to seek care Heavy bleeding or feeling faint? Get emergency help now. Emergency: 911

Not sure how urgent it is? Get help today.

  1. Emergency

    Heavy bleeding, black tarry stools, feeling faint, severe pain or trouble breathing.

    Call 911 or go to the ER.

  2. Today

    Fever, pain getting worse, a hot swollen lump, or trouble passing urine.

    Call your doctor or go to urgent care.

  3. Soon

    Bleeding or bowel changes nobody has checked, or anything lasting 3 weeks.

    Book a doctor’s appointment.

Feeling overwhelmed? Call or text 988, any time.

See all the signs

For this topic, get medical advice if you notice:

  • Foul or worsening smell with fever or increasing pain
  • Pus-like discharge that is increasing
  • Redness spreading around the wound
  • Feeling generally unwell

Recording how you feel is not the same as being checked. These are the signs that need a doctor’s attention.

Call 911 or go to the emergency room now if you have:

  • bleeding that will not stop, a lot of blood (the toilet water turns red, or you pass large clots), or any bleeding with feeling faint or dizzy
  • fainting, a racing heart or trouble breathing
  • confusion or slurred speech, extreme shivering, no urine in a day, or blotchy skin
  • sudden severe belly pain, or a swollen, hard belly with vomiting or not passing stool or gas
  • you cannot pass urine at all, or your bladder feels full and painful and you can’t empty it
  • redness, swelling or severe pain spreading quickly around your anus, genitals or groin, especially with a fever or feeling very ill
  • a fever with a painful swelling near your anus if you have diabetes or a weakened immune system (for example, from chemotherapy or transplant medicines)
  • black, tarry stools

Call your doctor or go to urgent care today (or the ER if you can’t be seen today) if you have:

  • a temperature of 100.4°F (38°C) or higher, chills, vomiting, or feeling generally unwell
  • pain that is getting worse over days, or severe pain that stops you sitting or sleeping
  • a hot, swollen or very tender lump near your anus or at the top of the crease between your buttocks, or foul-smelling discharge
  • trouble urinating
  • bleeding that is getting heavier or more frequent, or blood mixed into your stool
  • feeling much more tired than usual, looking pale, or getting out of breath more easily than you used to
  • not passing stool for several days, or new belly pain

Make an appointment with your doctor if:

  • you have never had these symptoms checked by a doctor or nurse — whatever your age
  • you have had rectal bleeding for more than 3 weeks
  • your bowel movements have been looser, thinner or more frequent than usual for 3 weeks or more, or you have lost weight without trying
  • symptoms have not settled after a week or so, or keep coming back
  • you notice a new lump near your anus, between your buttocks or in your belly, or an itch or discharge that does not clear
  • you have new leakage or trouble controlling your bowels
  • you are 45 or over, or have a family history of bowel cancer or inflammatory bowel disease, and any of these symptoms are new for you

If you are unsure, it is always reasonable to ask. If things feel overwhelming, call or text 988 (Suicide & Crisis Lifeline) or chat at 988lifeline.org, any time. If you don’t feel safe, call 911.

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