Home/Anal Fissures
Condition Deep-Dive

Anal Fissures

Small tears in the anal canal lining, usually from hard stool. They cause sharp pain during and after defecation. Most acute fissures settle within weeks with high fiber, fluids, stool softening (such as magnesium) and warm sitz baths.

Gut & Digestive Evidence-Based

Last updated:

โš ๏ธ Do not assume rectal bleeding is a fissure. A fissure typically causes sharp pain during and after a bowel movement, with bright blood on the paper. Bleeding without that pain, blood mixed into the stool, a change in bowel habit, weight loss, or any bleeding if you are over 45 or have a family history of colorectal cancer, needs medical assessment. Colorectal cancer screening starts at 45, and a fissure diagnosis you gave yourself is not a reason to skip it.7
Definition

What Are Anal Fissures?

Anal fissures are small linear tears or cracks in the lining of the anal canal, typically extending from the anal verge into the squamous epithelium. Most occur in the posterior midline and most of the rest at the front: in 623 people with an acute fissure, 64% were at the back, 21% at the front and 11% elsewhere13. They cause characteristic sharp tearing pain during defecation that often persists for hours afterward.

Most acute fissures (<6 weeks) heal with conservative management; in one trial, 87% of fissures healed within 3 weeks on sitz baths and bran10. Chronic fissures (>6 weeks) develop classic features: hypertrophied anal papilla above, sentinel skin tag below and visible internal sphincter muscle in the base. Underlying anal sphincter hypertonia maintains the fissure.

The pathophysiology centers on a vicious cycle: hard stool tears the lining โ†’ pain triggers sphincter spasm โ†’ reduced blood flow โ†’ impaired healing โ†’ chronic fissure. Fissures outside the typical midline locations (lateral, multiple) raise concern for underlying disease (Crohn's, HIV, tuberculosis, syphilis, anal cancer) and warrant evaluation.

๐Ÿ’ก Key Insight: The primary treatment is breaking the cycle: softening stool (high fiber, water, magnesium, stool softeners) and reducing sphincter spasm (sitz baths, topical nitrates or calcium channel blockers). It also takes patience: most acute fissures heal in 4 to 6 weeks. Surgery (lateral internal sphincterotomy) is reserved for chronic refractory cases.
A front cross-section of the anal canal with a small tear in its lining just inside the opening, a reddened inflamed area around it and the internal anal sphincter (the ring of muscle around the canal)

Types of Anal Fissures

Acute Fissure (<6 weeks)

Simple linear tear from hard stool. Most heal with conservative management. Posterior midline most common.2

Chronic Fissure (>6 weeks)

Persistent fissure with hypertrophied papilla, sentinel skin tag, visible sphincter. Sphincter spasm maintains it. Often requires more intensive treatment.

Atypical Fissure

Lateral location, multiple fissures, painless. Raises concern for Crohn's, HIV, TB, syphilis, anal cancer. Workup needed.

By the Numbers

Anal Fissures by the Numbers

~1 in 900
people a year were treated for an anal fissure in a US population study, most often at ages 25 to 34 15
87%
of first acute fissures had closed within 3 weeks on sitz baths and bran, in a randomized trial10
64%
of 623 acute fissures were in the posterior midline and 21% at the front13; a fissure anywhere else raises the question of Crohn's or infection7
>90%
success rate for lateral internal sphincterotomy in most series, the surgical option after other treatments fail5
15 to 40
the ages the NHS gives as most common (a US study found treatment peaked at 25 to 34 15), though young children get them too11
~50%
of fissures that closed with prescription ointment later came back, in a review of 75 randomized trials12
Signs & Symptoms

Symptoms of Anal Fissures

Characteristic pain pattern usually makes diagnosis straightforward. Atypical features warrant further evaluation.

SymptomWhat happens
Classic Symptoms
Sharp Tearing Pain with a Bowel MovementSevere, knife-like pain during bowel movement. Often described as passing broken glass. Typical of a fissure.
Persistent Burning Pain After a Bowel MovementAching, burning pain lasting minutes to hours after defecation. Worse with sphincter spasm. May be incapacitating.
Bright Red Blood on WipingSmall amounts of fresh blood on toilet paper, occasionally on stool surface. Never large volumes (suggests other diagnosis).
Fear of DefecationAnticipation of pain leads to stool holding, which worsens constipation โ†’ harder stool โ†’ more pain. Vicious cycle.
Atypical / Warning Features
Lateral or Multiple FissuresFissures outside the midline, or multiple fissures, raise concern for Crohn's, HIV, TB, syphilis, anal cancer. Need workup.
Painless FissureMost fissures are painful. Painless fissures suggest another diagnosis: Crohn's, syphilis, HIV, malignancy. Evaluate.
Significant BleedingLarge volumes of blood, dark blood, blood mixed with stool are not typical of a fissure. Investigate for IBD, polyps, cancer.
Anal Discharge / DrainageSuggests fistula formation. May indicate underlying Crohn's. Often presents with intermittent perianal swelling.
Causes

Causes of Anal Fissures

An anal fissure is a tear in the lining of the anus; it is not always clear what causes one, but the factors below make one more likely11.

CauseHow It Contributes to Anal FissuresWhat Helps
Constipation and hard stoolsPassing hard stool can tear the lining, and pain then makes people hold stool, which hardens it further; constipation is a common cause in children11Fiber, fluids, psyllium and magnesium as in the diet and supplement sections; in a trial, 87% of first acute fissures closed within 3 weeks on warm sitz baths and bran10
Frequent diarrheaHaving frequent diarrhea makes a fissure more likely11A clinician's assessment of the cause of ongoing diarrhea
Pregnancy and vaginal birthFissures are more likely in pregnancy and after a vaginal birth11Stool softening with fiber and fluids as in the diet section; a clinician can advise on treatments suitable in pregnancy
Tight anal sphincterSpasm of the internal sphincter reduces blood flow to the posterior midline, which keeps a fissure open2Warm sitz baths; prescription ointments or an injection that relax the muscle; a small cut in the muscle (sphincterotomy) if these fail
Inflammatory bowel diseaseCrohn's disease and ulcerative colitis can cause fissures, often off the midline or several at once117Specialist treatment of the bowel disease
Sexually transmitted infectionsInfections such as syphilis or herpes can cause fissures11Testing and treatment of the infection
Diagnosis

How Anal Fissures Are Diagnosed

TestWhat it shows
Clinical Examination
History & Symptom PatternClassic pain pattern with defecation + bright red blood. Constipation history. Often diagnostic without further testing.
Visual InspectionGentle separation of buttocks reveals fissure at posterior or anterior midline. Sentinel skin tag and hypertrophied papilla in chronic fissures.
Digital Rectal Exam (Often Deferred)Usually too painful in acute fissure. Often deferred until healing. If performed, may be done with topical anesthetic.
Bowel Habit AssessmentConstipation, hard stools, straining, hemorrhoids, diet, fiber intake, fluid intake. Identifies treatable factors.
Workup for Atypical Fissures
Anoscopy / SigmoidoscopyAfter healing for atypical features. Visualizes fissure, evaluates rectum for IBD, polyps, malignancy.
ColonoscopyFor age 45 and older (screening anyway), atypical features, persistent bleeding after fissure heals, family history of colon cancer.
Infection WorkupHIV test, syphilis, TB testing for atypical fissures. Cultures if discharge present.
IBD WorkupFecal calprotectin, CRP for suspected Crohn's. Anal fissures may be a presenting feature of Crohn's disease.
Treatment Comparison

Conventional and Holistic Treatment for Anal Fissures

๐ŸŒฟ HOLISTIC
๐Ÿ’Š CONVENTIONAL
๐ŸŒฟ

Holistic / Functional Approach

First-line for acute fissures.1 Most heal with conservative management. Treat constipation, a common trigger.

Healing Rate
In a trial of first acute fissures, 87% healed within 3 weeks on warm sitz baths and bran10
Core Strategy
Soften stool + warm sitz baths + sphincter relaxation + patience
Address the Cause
Treat constipation aggressively to prevent recurrence
Long-Term
Sustainable bowel habits prevent recurrence: daily fiber, hydration, a regular toilet schedule

Full Holistic Approach Includes

  • High-fiber diet (30 to 40 g/day), vegetables, fruits, whole grains, legumes, chia/flax seeds. Soft, formed stools help fissures close.
  • Adequate hydration (about 8 to 13 cups, 2 to 3 L, a day): fiber needs water to work.
  • Magnesium citrate 200 to 400 mg, gentle stool softening. Take at night. The top of this range is above the 350 mg/day upper intake level for supplemental magnesium; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
  • Psyllium fiber supplement: gradually increase to 1 to 2 tablespoons/day. Most evidence-based fiber.6
  • Stool softeners, docusate 100 to 200 mg/day; polyethylene glycol 17 g/day if needed
  • Warm sitz baths, 10 to 15 minutes, 2 to 3x/day. Especially after a bowel movement. Relaxes sphincter, improves blood flow, promotes healing.
  • Squatting position, using a toilet footstool. Improves anorectal angle, reduces straining.
  • Don't strain: relax during a bowel movement. If no stool comes in 5 to 10 minutes, get up and try later.
  • Topical preparations: petroleum jelly, zinc oxide, calendula creams for protection and comfort
  • Coconut oil application, anti-inflammatory, moisturizing; gentle barrier
  • Probiotics, may support regular bowel movements
  • Regular exercise: promotes regular bowel movements
  • Establish toilet routine, try same time daily, often after meals (gastrocolic reflex)
  • Avoid wiping hard: use moist wipes (alcohol-free), pat dry gently or use a bidet
  • Address underlying issues, opioid use, iron supplements (try slow-release or bisglycinate forms), pelvic floor dysfunction
  • Pelvic floor therapy, for sphincter dyssynergia or recurrent fissures
  • Be patient: healing can take 4 to 6 weeks, even with perfect care. Consistency matters more than aggressive treatment.
โœ… Conservative Care Works: most acute anal fissures heal with consistent conservative management focused on soft stool, sitz baths and addressing constipation. Treatment most often fails through inadequate attention to bowel habits.
Supplement Protocol

Evidence-Based Supplements for Anal Fissures

Focus on stool softening and constipation prevention.

SupplementWhat it is forTypical rangeTimingNotes & cautions
Psyllium FiberMost evidence-based fiber. Soft, bulky stools. Gradual approach to avoid gas.1 to 2 tablespoons/day in waterWith meals + waterStart with 1 tsp, gradually increase. Take with plenty of water.
Magnesium CitrateGentle stool softener via osmotic effect. Often deficient.200 to 400 mg/dayEveningEffective for constipation. Reduce if causing loose stools. The top of this range is above the 350 mg/day upper intake level for supplemental magnesium; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
Polyethylene Glycol (PEG)Osmotic laxative. Gentle, effective, well-tolerated.17 g/day (1 capful)Morning in waterExcellent option for chronic constipation. Safe for long-term use.
Docusate (Stool Softener)A surfactant that lets water into the stool to soften it. Best with adequate hydration.100 to 200 mg/dayWith foodUseful during initial healing. May not work alone for chronic constipation.
Probiotics (Multi-Strain)Support healthy gut microbiome and regular bowel movements.10 to 30 billion CFU/day, multi-strainWith or without foodEspecially after antibiotics. May reduce constipation.
Vitamin CMild laxative effect at higher doses. Supports collagen synthesis for tissue healing.500 to 2,000 mg/dayDivided dosesHigher doses cause loose stools, useful for constipation. The adult upper intake level is 2,000 mg a day, and the body converts vitamin C to oxalate, so if you have had kidney stones, ask your clinician first.
ZincAn essential mineral for skin and tissue; a benefit in fissures is unproven.15 to 30 mg/day during healingWith foodDon't exceed 30 mg long-term. 2 to 4 weeks during healing.

Collagen is not recommended here. No trial has tested it in anal fissure healing, and softening the stool does the work.8

What to Expect

What to Expect Over Time

Most fissures are short-lived tears; a minority last longer and need prescription or surgical treatment.

Treatment and supportive care, together
First Weeks

Soft stools, warm sitz baths and pain relief are the first steps; in a trial of first acute fissures, 87% had closed within 3 weeks on sitz baths and bran10. See a doctor if there is no improvement after 7 days of self-care.

Months 1 to 3

A fissure lasting more than 6 weeks is called chronic. A prescription ointment that relaxes the sphincter is often used for up to 8 weeks; across trials, fissures closed in 48.9% with nitrate ointment against 35.5% with placebo12.

Months 3 to 12

If ointments fail, an injection that relaxes the sphincter or a small cut in the muscle (sphincterotomy) may be offered. Sphincterotomy succeeds in over 90%5, but about 14% of people followed for 2 years or more have some lasting change in continence, most often to gas14.

Long Term

Fissures often come back: about half of those that closed with ointment recurred later12. Keeping stools soft with fiber and fluids is the main long-term measure.

When to Seek Care

Do not assume bleeding is from a fissure. See a clinician about bleeding without the typical pain, blood that is dark, heavy or mixed into the stool, or bleeding with a change in bowel habit, weight loss, unusual tiredness or anemia, since these can signal colorectal cancer or inflammatory bowel disease. A fissure off the midline, several fissures or a painless one also needs assessment. Go to emergency care for heavy or nonstop bleeding.

📬

Get new guides in your inbox. Once a month: new condition guides and research updates, including the trials that did not work. Free, no spam, and you can unsubscribe in one click.

Sign up

Next Steps

Keep Stools Soft

Most acute anal fissures close with consistent conservative care focused on soft stools and sphincter relaxation; chronic ones may need prescription treatment. The key is breaking the pain-spasm cycle while addressing the underlying constipation that caused the fissure. Be patient: healing can take 4 to 6 weeks. Establish long-term bowel habits to prevent recurrence.

Explore Hemorrhoids โ†’ Explore IBS & IBD โ†’

References & Evidence Notes

Each numbered entry below is either a source you can follow or a note setting out what the evidence does and does not support. Both are numbered together so the markers in the text line up.

Last reviewed October 20, 2026. Supplement entries are cross-checked against the NIH National Center for Complementary and Integrative Health and the Linus Pauling Institute Micronutrient Information Center.9 This page is nutrition education, not medical advice. One thing here is different from most pages on this site: conservative care genuinely is first-line treatment for an acute anal fissure, not an adjunct to it. Soft stool, sitz baths and time heal the large majority. That said, two cautions. Do not assume rectal bleeding is a fissure, because bleeding is also how colorectal cancer and inflammatory bowel disease present. And a fissure that has not healed in six weeks, or one that is off the midline, multiple or painless, needs a clinician rather than more fiber.

  1. On conservative management: acute anal fissures, defined as under six weeks' duration, heal in the large majority of patients with stool softening, adequate fiber, warm sitz baths and time. Guidelines from colorectal surgical societies place this first, ahead of any pharmacological or surgical option, because it works and carries no risk of incontinence; the American Society of Colon and Rectal Surgeons' 2023 guideline states that nonoperative treatment of acute anal fissures should typically be first-line, PubMed 36321851. ↩
  2. On the underlying mechanism: the posterior midline anal canal has the poorest blood supply, which is why fissures occur there and why internal sphincter spasm perpetuates them. Relieving spasm improves perfusion, which is the shared logic behind sitz baths, topical nitrates, calcium channel blockers, botulinum toxin and sphincterotomy. ↩
  3. On topical treatment: topical nitrates (nitroglycerin) and topical calcium channel blockers (diltiazem, nifedipine) both relax the internal sphincter and improve healing rates over placebo in chronic fissures. Headache is a major side effect of nitrates: in a randomized trial it affected 17 of 29 people on nitrate ointment against 8 of 31 on a calcium channel blocker cream, with no difference in how many fissures healed, PubMed 11952579. Calcium channel blockers have a lower headache rate with broadly comparable healing. ↩
  4. On botulinum toxin: injection into the internal anal sphincter produces temporary chemical relaxation, with healing rates between topical therapy and surgery, and a lower incontinence risk than sphincterotomy. Effect wears off over months, and recurrence is common. ↩
  5. On lateral internal sphincterotomy: the most effective treatment for chronic fissure, with healing rates above 90% in most series, PubMed 40679512, and the reference standard against which the others are measured. The trade-off is real and belongs in the decision: a review of 22 studies following people for 2 years or more found some change in continence in 14%, most often to flatus (9%), PubMed 23320551, and it is generally permanent because the sphincter division is. This is why it follows failed conservative and topical treatment rather than preceding them. ↩
  6. On fiber: psyllium and other soluble fiber supplements reduce recurrence of anal fissure by keeping stool soft and bulky, and fiber has the best evidence of any dietary measure here. Increase gradually with fluid, since a sudden large increase causes bloating and can worsen straining. ↩
  7. On not self-diagnosing rectal bleeding: anal fissure classically causes sharp pain during and after defecation with bright red blood on the paper. Bleeding that is painless, mixed through the stool, or accompanied by a change in bowel habit or weight loss, has a different differential including colorectal cancer, inflammatory bowel disease and hemorrhoids. Average-risk colorectal cancer screening begins at 45 in current US guidance. Atypical fissures (lateral rather than midline, multiple or painless) additionally raise the possibility of Crohn's disease, HIV, tuberculosis, syphilis and anal cancer, and warrant evaluation. ↩
  8. On collagen supplementation: hydrolyzed collagen provides glycine, proline and hydroxyproline, and has modest trial evidence in skin and joint outcomes. There is no trial evidence for collagen in anal fissure healing, so this guide does not recommend it. The measures that heal fissures are the ones that soften stool and relax the sphincter. ↩
  9. National Center for Complementary and Integrative Health (NIH), nccih.nih.gov, and the Linus Pauling Institute Micronutrient Information Center, lpi.oregonstate.edu/mic. ↩
  10. On conservative care for a first acute fissure: in a randomized trial of 103 patients with a first acute posterior fissure, 87% of those given warm sitz baths and unprocessed bran for three weeks had healed, against 60% of those given lidocaine ointment, PubMed 3011180. Sitz baths with bran also gave the quickest relief of symptoms and carry no serious side effects. ↩
  11. On who gets anal fissures and why: they are more common in people aged 15 to 40 and in young children, and are more likely with constipation, frequent diarrhea, pregnancy or a vaginal birth, inflammatory bowel disease, and sexually transmitted infections such as syphilis or herpes; most get better on their own, and a doctor should be seen if there is no improvement after 7 days of self-care, NHS. ↩
  12. On prescription treatment: a review of 75 randomized trials with 5,031 participants found nitrate ointment only marginally better than placebo for chronic fissure (48.9% against 35.5% closed), with late recurrence in about half of those that closed; injections and calcium channel blocker ointments were as effective with fewer side effects, and no medical therapy came close to surgery, PubMed 22336789. ↩
  13. On where fissures occur: in a German referral center series of 623 people with an acute anal fissure, 64% of fissures were in the posterior midline (6 o'clock), 21% in the anterior midline (12 o'clock) and 11% in an atypical position; front fissures were more common in women, and 70.5% of fissures healed completely, PubMed 41493654. ↩
  14. On continence after sphincterotomy: a systematic review of 22 studies with 4,512 patients followed for 2 years or more after lateral internal sphincterotomy found some continence disturbance in 14%, most often to gas (9%), with soiling in 6% and loss of liquid or solid stool in under 1%; the authors call the long-term risk significant, PubMed 23320551. ↩
  15. On how common fissures are: in a US population-based study of a large managed care system from 2005 to 2011, 1,243 people aged 6 and over were treated for an anal fissure, an annual incidence of 1.1 per 1,000 person-years, highest at ages 25 to 34; constipation, obesity and an underactive thyroid were more common in people with a fissure, PubMed 25027411. ↩