If you’ve ever had an anal fissure, you know they’re far more than “just a cut.”
Patients often tell me that passing a bowel movement feels like pooping shards of glass, followed by hours of burning, throbbing pain that makes them dread going to the bathroom again. That fear leads many people to avoid bowel movements, which only makes constipation worse—and the fissure even harder to heal.
One of the most common questions I hear is:
“Will Botox fix my fissure? And will I need more than one injection or injections forever?”
An anal fissure is a small tear in the lining of the anal canal. While the tear itself is painful, the real problem is what happens afterward.
The internal anal sphincter, a muscle that normally stays tightly closed to maintain continence, often goes into spasm after a fissure develops. Think of it like getting a charley horse in your calf—but in your bottom.
That muscle spasm decreases blood flow to the fissure, making it difficult for the wound to heal. The cycle becomes:
Pain → muscle spasm → decreased blood flow → poor healing → more pain.
Most people know Botox from cosmetic treatments, but in colorectal surgery we use it for a completely different reason. If I had a nickel for every time a patient asked me if I could “inject a little into their crow’s feet”…
Botox temporarily relaxes the internal anal sphincter. This process is sometimes called chemical sphincterotomy, meaning we relax the muscle without permanently cutting it.
When the sphincter relaxes:
Blood flow improves
Pain decreases
The fissure has a chance to heal naturally
Bowel movements become less traumatic
Unlike surgery, Botox is temporary. The medication gradually wears off over approximately 3 to 6 months, but this gives the fissure time to heal while preserving the muscle.
The good news is that Botox is an effective treatment for many patients with chronic anal fissures.
Large studies have shown healing rates between 60% and 80%, depending on the dose used, patient selection, and study design.
The American Society of Colon and Rectal Surgeons (ASCRS) recommends botulinum toxin as an evidence-based treatment for chronic anal fissure. It can be used as an alternative to surgery or after topical medications, such as nitroglycerin or calcium channel blockers, have failed.
Botox is particularly attractive for patients who want to avoid an operation or who may have a higher risk of incontinence after surgery.
Maybe—but not always.
This is one of the biggest misconceptions about Botox.
Some patients heal completely after a single treatment. Others require a second injection if the fissure hasn’t healed after several weeks.
One landmark study by Menteş and colleagues evaluated patients approximately two months after their first injection. Patients whose fissures had not healed received a second injection, increasing the overall healing rate from about 74% to nearly 87%.
In other words, a second injection can rescue many patients who don’t respond the first time.
Most colorectal surgeons reassess patients about 6–8 weeks after Botox. If the fissure is improving but not completely healed, repeating the injection is often reasonable before moving on to surgery.
Researchers have wondered whether giving a larger dose of Botox the first time could reduce the need for repeat injections.
Some individual studies—including work by Brisinda and colleagues—suggest that higher doses may improve initial healing rates.
However, when researchers combined all of the available studies into larger meta-analyses, the results became much less clear.
The 2023 ASCRS Clinical Practice Guideline concluded that there is no universally accepted optimal Botox dose, and studies vary widely in how much medication they use, where they inject it, and how many injections they perform.
So while some surgeons favor higher-dose protocols, there isn’t enough evidence yet to say that everyone should receive more Botox up front.
Not necessarily.
The gold standard surgical treatment is called lateral internal sphincterotomy (LIS).
LIS has healing rates exceeding 90%, making it the most effective treatment for chronic anal fissures.
However, surgery permanently divides a portion of the internal sphincter. Although most patients do very well, there is a small risk of long-term gas or stool leakage, especially in women with prior childbirth injuries or patients who already have weakened pelvic floor muscles.
Botox offers a middle ground.
It provides a reversible, sphincter-preserving option with a lower risk of permanent continence problems, although healing rates are generally lower than surgery and recurrence is somewhat more common.
Botox isn’t the only botulinum toxin available.
Other formulations are under the brand names Dysport and Xeomin.
Current evidence suggests they work similarly when equivalent doses are used, and it’s just that most research studied Botox (onabotulinum toxin), and not the other formulations. Dysport is abobotulinum toxin and Xeomin is incobotulinum toxin. Why do these sound like elvish names? I am Abo of the botulinum toxin clan.
The major colorectal surgery guidelines do not recommend one brand over another. Instead, they refer to botulinum toxin type A as a class of medications.
Your surgeon’s experience, medication availability, and dosing preferences usually determine which product is used.
If you’re struggling with a chronic anal fissure, remember that you have options.
Botox can interrupt the cycle of pain and muscle spasm, allowing the fissure to heal without permanently altering the anal sphincter.
Some patients need only one injection. Others benefit from a second treatment after about two months. And while surgery remains the most effective option for many patients, Botox provides an excellent sphincter-preserving alternative for the right person.
The most important step isn’t choosing Botox versus surgery.
It’s getting evaluated before months—or years—of pain become your new normal! Your butt deserves better.
Next week, we’ll discuss whether butt Botox, also called Holetox, might help those who have anal receptive intercourse.
Until next time, that’s just the way the anus wrinkles.
