How does botox help a fissure heal?

Botox (botulinum toxin) works by temporarily paralysing the internal anal sphincter muscle. This reduces the spasm that restricts blood flow to the fissure. With improved blood flow and reduced tension, the fissure has a better environment for healing. The effect is temporary — typically lasting two to three months — but this window is often enough for the fissure to heal.

Is the botox injection painful?

The injection is done under sedation or general anaesthesia in most cases, so you do not feel the injection itself. Some people report mild soreness at the injection site for a day or two afterwards, but most describe the procedure as surprisingly uneventful.

How long does the botox effect last?

The muscle-relaxing effect typically lasts two to three months. During this window, the reduced sphincter tension allows the fissure to heal. After the botox wears off, the sphincter gradually regains its normal tone. If the fissure has healed during this time, it may not recur.

What is the success rate of botox for fissures?

Studies and clinical experience suggest that botox heals chronic fissures in roughly 50 to 70 percent of cases. This is higher than topical treatments alone but lower than surgical sphincterotomy. Botox is often tried before surgery because it is less invasive and carries a lower risk of incontinence.

Can botox cause incontinence?

Temporary changes in gas control are reported by a small percentage of people after botox injection. Significant incontinence is uncommon and, when it occurs, is temporary — it resolves as the botox wears off. This is one of the advantages of botox over surgery: any side effects are reversible.

Botox for anal fissure explained

At a glance

Botox (botulinum toxin) injection is a treatment for chronic anal fissures that have not responded to conservative measures and topical treatments. It works by temporarily relaxing the internal sphincter muscle, improving blood flow, and creating a healing window. The procedure is brief, usually done as a day case, and the recovery is typically straightforward.

How it works

The mechanism is similar to topical treatments like GTN and diltiazem, but more direct and more potent:

Injection into the sphincter — botox is injected directly into the internal anal sphincter muscle
Muscle relaxation — the botox blocks nerve signals to the muscle, causing it to relax
Improved blood flow — reduced spasm means better circulation around the fissure
Healing window — the relaxation lasts two to three months, providing sustained conditions for healing

The key advantage over topical treatments: botox provides consistent, round-the-clock sphincter relaxation. Topical treatments need to be applied multiple times daily and their effect fluctuates.

The procedure

Botox for fissure is typically done as a day case procedure:

Duration: The injection itself takes a few minutes
Anaesthesia: Usually brief general anaesthesia or sedation
Setting: Day surgery — you arrive, have the procedure, and go home the same day
What happens: The surgeon injects a small amount of botulinum toxin into the internal sphincter muscle, usually at one or two sites
Going home: Most people leave within a few hours of the procedure

Recovery

The recovery from the injection itself is minimal:

Day 1 to 3: Mild soreness at the injection site. Otherwise, most people feel back to normal quickly.
Day 3 to 14: The botox gradually takes effect. The sphincter relaxes progressively over this period.
Week 2 onwards: Most people notice improvement in fissure symptoms — less pain, shorter post-bowel-movement discomfort, easier bowel movements.

The important self-care during recovery:

Continue stool softening (fibre, hydration, softeners)
Continue sitz baths
Do not stop the self-care routine just because symptoms improve — the fissure needs the full healing window

When botox is recommended

Botox is typically considered when:

Conservative measures (dietary changes, stool softening) have been tried
Topical treatments (GTN, diltiazem) have been tried for an adequate period and have not healed the fissure
The fissure is chronic (present for more than six to eight weeks)
The patient prefers a less invasive option than surgery

After botox

If it works

Many people describe gradual improvement over two to four weeks, followed by a period of relative comfort while the botox is active. The fissure heals during this window. If it heals completely, it may not recur — though maintaining good bowel habits remains important.

If it partially works

Some people experience improvement but not complete healing. In these cases, a second injection or escalation to surgery may be discussed.

If it does not work

Botox does not work for everyone. If there is no improvement after two to three weeks, the conversation about next steps — a second injection or surgery — typically begins. Our guide on what to do when botox does not work covers these options.