Most anal fissures heal within a few weeks with simple at-home measures: more fiber, warm soaks, and keeping stools soft. The key is breaking the cycle that keeps the tear from closing. When you pass a hard stool, the small tear in the lining of the anal canal causes pain, which triggers the surrounding muscle to spasm. That spasm reduces blood flow to the area, which slows healing, so the tear is still raw the next time you have a bowel movement. Everything you do to heal a fissure targets one or more parts of that cycle.
Why Fissures Get Stuck in a Pain Cycle
The anal canal is lined with thin, delicate tissue that has a limited blood supply, especially along the back wall where most fissures form. When a tear occurs, the internal sphincter muscle (the ring of muscle that keeps the canal closed) begins to spasm with each bowel movement. The spasm is painful on its own, but it also squeezes the small blood vessels that feed the injured tissue. With less blood reaching the wound, healing slows dramatically. Some fissures persist for months because of this feedback loop: pain causes spasm, spasm restricts blood flow, poor blood flow prevents healing, and the unhealed tear keeps hurting.
Breaking any link in that chain speeds recovery. Softer stools reduce the initial pain trigger. Warm water relaxes the sphincter. Topical medications force the muscle to relax and open up blood flow. Surgery, when needed, permanently loosens the muscle. The right approach depends on how long you’ve had the fissure and how it responds to conservative care.
Fiber, Fluids, and Stool Softening
The single most important thing you can do is make your stools soft enough that they pass without straining or re-tearing the wound. That starts with fiber. The general recommendation is 25 grams per day for women and 38 grams per day for men. Most people fall well short of that. You can close the gap with high-fiber foods like beans, lentils, oats, berries, broccoli, and whole grains, or with a fiber supplement like psyllium husk. If you’re not used to eating much fiber, increase gradually over a week or two to avoid bloating and gas.
Fiber only works if you’re also drinking plenty of water. Without enough fluid, extra fiber can actually make stools harder. There’s no single magic number, but aim to drink enough that your urine stays pale yellow throughout the day. Staying well-hydrated keeps fiber moving through the digestive tract and forming the soft, bulky stool that passes easily.
If fiber and water alone aren’t enough, an over-the-counter stool softener can help in the short term. The goal isn’t loose or watery stools. You want a consistency that’s easy to pass without bearing down.
Sitz Baths and Topical Care
A sitz bath is simply sitting in a few inches of warm water so the anal area is submerged. The warmth relaxes the internal sphincter, temporarily increasing blood flow to the fissure and easing pain. Cleveland Clinic recommends water at about 104°F (40°C) for 15 to 20 minutes per session. Two to three times daily is typical, and after every bowel movement if you can manage it.
You can use a shallow basin that fits over your toilet seat or just sit in a regular bathtub with a few inches of water. Skip soaps, bubble bath, or Epsom salts in the water, as these can irritate broken skin. Pat the area dry gently afterward. Some people find that applying a thin layer of petroleum jelly to the fissure after the bath helps protect the tissue and reduces friction during the next bowel movement.
Prescription Topical Treatments
When home measures aren’t enough after a few weeks, prescription ointments can help by chemically relaxing the sphincter muscle. Two options are most commonly used.
Nitroglycerin ointment works by releasing nitric oxide, which relaxes smooth muscle and widens blood vessels around the fissure. Healing rates in clinical studies hover around 50%, which is comparable to placebo in some trials, suggesting that part of the benefit comes from the overall treatment regimen (fiber, baths, consistent care) rather than the drug alone. The main side effect is headache, which is dose-related. About 3% of patients stop treatment because of headaches.
Diltiazem ointment relaxes the sphincter through a different mechanism. In head-to-head comparisons, it heals fissures at roughly the same rate as nitroglycerin but causes 60% fewer headaches. It also has a 30% lower recurrence rate, meaning fissures that heal with diltiazem are less likely to come back. For these reasons, many providers now prefer it as the first-line prescription option.
Both ointments are applied directly to the anal canal, typically twice daily for six to eight weeks. You may notice pain relief within days, but the tissue itself takes longer to fully close.
Botulinum Toxin Injections
If topical treatments fail, an injection of botulinum toxin (the same compound used in cosmetic procedures) into the internal sphincter is the next step before surgery. The injection temporarily paralyzes part of the muscle, breaking the spasm cycle for several months while the fissure heals.
Results are strong. In one study, 89% of patients had a healed fissure one month after the injection, and 94% were healed at two months. The small number who didn’t heal after the first injection received a second dose, and all of them healed within a month after that. In a two-year follow-up, none of the treated patients reported recurrence or problems with bowel control. The procedure is done in an office or outpatient setting and doesn’t require general anesthesia.
Surgery for Fissures That Won’t Heal
Lateral internal sphincterotomy is the standard surgical option for chronic fissures that haven’t responded to other treatments. The surgeon makes a small cut in the internal sphincter muscle to permanently reduce its resting tension. This restores blood flow to the area and eliminates the spasm cycle for good.
The procedure has a 95% success rate and a recurrence rate of only about 3%. It’s typically done as an outpatient procedure, and recovery takes a few weeks. The trade-off is a small risk of changes to bowel control. Up to half of patients experience some short-term issues like minor leakage of gas or stool during recovery, but these almost always resolve. Long-term incontinence is rare, with most estimates below 5%, and when it does occur, it’s usually minimal. Because of this risk, surgery is generally reserved for fissures that have resisted everything else.
What Healing Looks Like Over Time
Acute fissures, the ones you’ve had for less than six to eight weeks, often heal with fiber, fluids, and sitz baths alone. Pain typically starts improving within the first week of consistent care, though the tissue itself may take four to six weeks to fully close. During this time, you might notice that bowel movements still cause some discomfort, but the sharp, tearing pain should gradually become less intense.
Fissures that persist beyond eight weeks are considered chronic. These develop thickened edges and sometimes a small skin tag at the outer end of the tear. Chronic fissures are much less likely to heal on their own because the scar tissue and ongoing spasm have become self-reinforcing. This is the point where prescription ointments, injections, or surgery become necessary.
Even after a fissure has healed, the area remains somewhat vulnerable to re-injury. Maintaining a high-fiber diet, staying hydrated, and avoiding straining during bowel movements are the most reliable ways to prevent a new tear from forming. If you tend toward constipation, keeping a fiber supplement as part of your daily routine, rather than only using it during flare-ups, makes recurrence far less likely.