Anal Fissure & Fistula Support

Anal Fissure & Fistula: A Nutritional and Natural-Health Reference

1. Definition and Clinical Overview

Anal Fissure

An anal fissure is a painful linear tear or crack in the distal anal canal, which, in the short term, usually involves only the epithelium and, in the long term, involves the full thickness of the anal mucosa. More specifically, it is a longitudinal tear of the anoderm distal to the dentate line and is a frequent cause of emergency department visits.

Fissures are defined as acute if present for less than 8 weeks, and they are defined as chronic if present for more than 8–12 weeks and feature edema and fibrosis. Chronic anal fissures persist as nonhealing ulcers driven by anal sphincter spasm and resulting ischemia.

Posterior midline fissures are the most common location; they are often associated with increased anal sphincter tone and reduced blood flow to the posterior commissure, leading to ischemia and delayed healing. Anterior midline fissures are more frequently observed in women, likely due to anatomical location and childbirth-related trauma. Lateral fissures are rare and should prompt evaluation for uncommon underlying conditions, such as carcinoma or infections.

Hypertonicity of resting pressure of the internal anal sphincter is seen in patients with fissures as compared with normal controls, which can induce pain and spasm with defecation, and it also has an unfavorable effect on wound healing by reducing blood flow to the traumatized anoderm.

Anal Fistula

An anal fistula is an inflammatory tract between the anal canal and the skin. Most anal fistulas originate in anal crypts, which become infected, with ensuing abscess formation. When the abscess is opened or when it ruptures, a fistula is formed.

The four categories of fistulas, based on the relationship of fistula to sphincter muscles, are intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric. An anal fistula can also be categorized as either simple or complex.

Perianal abscesses, which cause cryptoglandular anal fistula, are caused by cryptoglandular infections. Not every abscess will end in a fistula. The formation of a fistula is determined by the anatomy of the anal sphincter, and perianal fistulas will not heal on their own.

Clinical Presentation

Anal fissures may present with rectal pain described as burning, cutting, or tearing that occurs with bowel movements. It is a painful condition that can last for up to two hours during and after defecation.

Perianal abscesses are another source of pain, often exacerbated during defecation, and may be accompanied by bleeding. These abscesses can progress to anal fistulas, which may present with bleeding or purulent discharge.

Anal fissures develop with equal frequency in both sexes; they tend to occur in younger and middle-aged persons.

Body Systems Involved

The anorectal region integrates several anatomical and physiological systems in these conditions. The key structures involved include the anoderm (the specialized squamous epithelium lining the anal canal), the internal anal sphincter (IAS), the external anal sphincter, the dentate line, the anal crypts, and their associated glands. Evidence suggests that blood flow to the anal canal and internal anal sphincter tone play a role in the development and healing of anal fissures. Decreased blood flow has been described in chronic, nonhealing fissures. Hypertonicity of the internal sphincter may also cause decreased blood flow in the area of a fissure. The gastrointestinal system governs stool consistency and transit — a primary mechanical factor — while the immune system's inflammatory response underpins both the acute reaction and the chronic non-healing state. Additionally, fistulas are found in patients with inflammatory bowel disease, particularly Crohn disease.

2. Contributing and Associated Factors

Mechanical and Traumatic Triggers

Most fissures result from local trauma to the anoderm, commonly due to passage of hard or bulky stools, persistent irritation, anorectal surgery, or anoreceptive intercourse. Common causes include constipation, chronic diarrhea, sexually transmitted infections (STIs), tuberculosis, inflammatory bowel disease (IBD), HIV, anal cancer, obstetric trauma, prior anorectal surgery, and anoreceptive intercourse.

Dietary and Nutritional Factors

Low intake of dietary fibre may be a risk factor for anal fissure. Anal fissures are often associated with the passage of hard stools or anal trauma, but the exact etiology often remains unclear. Dehydration, by promoting firmer stools, is also implicated in the mechanical chain of events leading to fissure formation.

Inflammatory and Systemic Disease

Other risk factors for anal fissures include inflammatory bowel disease, AIDS, colorectal cancer, and skin conditions like psoriasis or pruritus. The incidence of fissures in Crohn disease is 30–50%. In the context of anal fistula, anal cancer, Crohn's disease, diabetes, smoking, obesity, and an immunocompromised condition such as HIV are among identified risk factors.

Vascular and Sphincter Physiology

Hypertonicity of resting pressure of the internal anal sphincter is seen in patients with fissures as compared with normal controls, which can induce pain and spasm with defecation, and it also has an unfavorable effect on wound healing by reducing blood flow to the traumatized anoderm. This ischemic microenvironment is central to the chronification of fissures and is a target for several nutritional and phytotherapeutic interventions.

Recurrence Factors for Anal Fistula

A 2019 meta-analysis of 20 observational studies comprising 6,168 patients (published in the International Journal of Surgery) found that: high-quality evidence showed that anal fistula recurrence (AFR) was associated with high transsphincteric fistula (RR, 4.77), internal opening unidentified (RR, 8.54), and horseshoe extensions (RR, 1.92). Moderate-quality evidence suggested an association with prior anal surgery (RR, 1.52), seton placement surgery (RR, 2.97), and multiple fistula tracts (RR, 4.77). Notably, high-quality evidence demonstrated no significant association with gender or smoking; moderate-quality evidence also suggested no association with age, alcohol use, diabetes mellitus, or obesity for fistula recurrence specifically.

More broadly, risk factors for delayed wound healing after anal fistula surgery include patient-related factors such as diabetes, smoking, obesity, and nutritional status, and procedure-related factors such as surgical technique and postoperative infection.

3. Dietary Factors Discussed in Authoritative Sources

Dietary Fiber

Dietary fiber occupies the most authoritative position among nutritional factors in the management of anal fissure and, to a lesser extent, fistula-related anorectal health. All four major international guidelines — WSES/AAST, ACG, ACPGBI, and ASCRS — recommend dietary fiber, stool softeners, hydration, and sitz baths for acute fissures.

Initial management of anal fissures typically involves a 6-week trial of conservative measures. Recommended strategies include frequent sitz baths, analgesics, stool softeners, and a high-fiber diet to facilitate healing and reduce recurrence. Adequate hydration is also advised to minimize the risk of recurrent fissures.

Maintenance fiber supplementation — for example, psyllium — after healing reduces recurrence. No single fiber type is superior.

Fiber's role in anorectal conditions is also well-supported for hemorrhoids, to which it is closely related: fiber supplementation has been proven to reduce the incidence of bleeding and persisting symptoms in hemorrhoid patients by around 50%, and is recommended by the American Society of Colon and Rectal Surgeons (ASCRS) practice guidelines.

Hydration

Adequate fluid intake is consistently co-recommended with fiber across guidelines. Dehydration promotes hard stools, increases straining during defecation, and thus amplifies mechanical trauma to the anoderm. Adequate hydration is also advised to minimize the risk of recurrent fissures. Water is an important factor in wound healing but is often overlooked.

Protein and Amino Acids

Protein is broadly established as essential to mucosal and wound repair through its provision of amino acid building blocks. Protein provides the amino acids necessary for the synthesis of new tissue, enzymes, and immune cells. Protein-energy malnutrition can significantly impair wound healing, leading to delayed healing times and increased risk of infection.

Lipids and Omega-3 Fatty Acids

Omega-3 fatty acids and specific amino acids have been linked to enhanced wound-healing and immune function in the nutritional wound-healing literature, though this evidence is not specific to the anorectal context. Lipids provide energy for wound healing and proliferation, act as building blocks for epidermal and dermal tissues, and are involved in the synthesis of cell membranes and the composition of the intracellular matrix.

4. Nutrients Studied or Traditionally Used

4.1 Vitamin C (Ascorbic Acid)

Scientific Evidence (general wound healing; not anal fissure-specific)

Vitamin C is involved in all phases of wound healing. It exhibits strong antioxidant properties and facilitates fibroblast activity, angiogenesis, and immune regulation during the inflammatory and proliferative phases. The antioxidant properties of vitamin C make it a key player in protecting the immune system and reducing inflammatory responses.

Vitamin C (ascorbic acid) is necessary for collagen synthesis and stabilizes collagen's triple-helical structure. A deficiency in vitamin C can lead to weakened collagen and impaired wound healing.

Evidence strength: The role of vitamin C in collagen synthesis and general wound healing is well-established in the basic and clinical literature. However, many studies and reviews found unclear benefits to vitamin and mineral supplementation unless patients had confirmed or suspected nutritional deficiencies. A 2014 Cochrane review of 23 studies found no clear evidence for the use of nutritional supplementation in pressure ulcers. No high-quality clinical trials have specifically addressed vitamin C supplementation for anal fissure or fistula healing.

4.2 Zinc

Scientific Evidence (general wound healing; not anal fissure-specific)

Vitamins A, C, and E, as well as minerals such as zinc, selenium, and iron, are essential for cell proliferation and the formation of new tissues. Specifically, zinc is involved in cell proliferation and contributes to wound reconstruction. Iron forms hemoglobin, which is important for tissue perfusion throughout the healing process and aids in collagen synthesis.

In the proliferative phase of wound healing, zinc is required for DNA and protein synthesis. Zinc is a cofactor in collagen synthesis that aids in collagen maturation.

Evidence strength: Zinc's role in general tissue healing is supported by preclinical and some clinical data. One small study examined the effects of topical zinc oxide for acute open wounds and found significant decreases in Staphylococcus aureus infections (p<0.05) and post-op antibiotic use (p<0.005), and also showed a decrease in median healing time. Direct human trials in anal fissure or fistula populations are absent from the peer-reviewed record at this time.

4.3 Vitamin A

Scientific Evidence (general wound healing; not anal fissure-specific)

Vitamin A plays a crucial role in epithelialization, the process by which new skin cells form to cover the wound. It also supports immune function and has anti-inflammatory properties. Vitamin A deficiency can compromise the immune response, thereby increasing the susceptibility of wounds to infections. Both local (topical) and systemic vitamin A supplementation have been shown to increase dermal collagen deposition.

Evidence strength: Preliminary. The potential benefits of vitamin A supplementation must be weighed against the associated risks, as vitamin A toxicity can be critical. Therapeutic studies are needed to establish the efficacy and safety of vitamin A supplementation in the context of wound healing, and further research is needed to establish optimal dosage and safety guidelines. No clinical trials specifically addressing anal fissure or fistula have been identified.

4.4 L-Arginine

Scientific Evidence — Human Clinical Trials

L-Arginine is the most extensively studied natural supplement with direct evidence in the anal fissure context. Its rationale stems from its role as the physiological precursor to nitric oxide (NO), a potent smooth-muscle relaxant. Local application of exogenous nitric oxide donors, such as isosorbide dinitrate and glyceryl trinitrate, promotes fissure healing by reducing anal resting pressure and improving anodermal blood flow. The major drawback of these nitric oxide donors is headache, with an overall incidence of approximately 40 percent. L-arginine, being an intrinsic precursor of nitric oxide, reduces anal resting pressure without headache as a side effect.

A phase II study published in Diseases of the Colon & Rectum tested topical L-arginine gel in 15 chronic anal fissure patients. Local application of L-arginine promoted fissure healing without headache as a side effect, and L-arginine was effective even in patients not responding to isosorbide dinitrate treatment.

A 2023 randomized, double-blind, placebo-controlled trial (published in Amino Acids) assessed oral L-arginine: this was a randomized, double-blind, placebo-controlled trial with parallel design conducted in 4-week intervention and 8-week follow-up phases, recruiting 76 adult men and women (aged 18–65 years) with chronic fissures. Participants took a 1,000 mg capsule three times a day for one month, and were then followed at the end of the first and third months after the intervention. Oral L-arginine supplementation at 1 g three times a day showed superior improvements in fissure size, bleeding, wound healing, and pain compared to the placebo group. Resting anal sphincter pressure notably decreased in the L-arginine group, suggesting potential therapeutic benefits.

Evidence strength: Moderate — supported by a phase II clinical study and one small randomized controlled trial in the chronic anal fissure population. Limitations include small sample sizes and the single-center nature of the available trials. This was stated by the study authors to be the first study evaluating the effect of oral L-arginine as a safer method with better performance on clinical symptoms, quality of life, and internal anal sphincter pressure in patients with chronic anal fissure. Larger multicenter trials are required before firm conclusions can be drawn.

5. Herbs and Natural Ingredients

5.1 Aloe Vera (Aloe barbadensis Miller)

Traditional Use

Aloe vera has an exceptionally long history in global traditional medicine. Early civilizations used Aloe vera for skin care, to relieve insect stings and bites, to treat scratches and ulcerated skin, to promote wound healing, to prevent hair loss, and as a purgative. It was the traditional medicine of many cultures as an anthelmintic, cathartic, and stomachic and was used for burns and allergic conditions. In Ayurvedic and traditional Persian medicine, Aloe preparations were applied topically to wounds and mucosal surfaces to promote healing and reduce inflammation.

Scientific Evidence

A prospective double-blind clinical trial (published in European Review for Medical and Pharmacological Sciences, 2014; PMID 24763890) evaluated a topical cream containing 0.5% Aloe vera juice powder in chronic anal fissure patients. The Aloe cream was applied 3 times per day for 6 weeks. Pain was assessed with a visual analog scale before treatment and at the end of each week. Wound healing and the amount and severity of bleeding were examined before and at the end of each week of treatment. There were statistically significant differences in chronic anal fissure pain, hemorrhaging upon defecation, and wound healing before and at the end of the first week of treatment compared with control group (p < 0.0001). The topical cream containing Aloe vera juice was assessed as an effective treatment for chronic anal fissures.

In a broader systematic review of Aloe vera clinical trials on wound healing (PMC6330525): Aloe vera has been effective in chronic wounds such as pressure ulcers, diabetic ulcers, chronic anal fissure wounds, and chronic wounds caused by accidents. Aloe vera reduced pain, bleeding, and recovery time in chronic wounds.

An animal (rat) study published in Revista do Colégio Brasileiro de Cirurgiões evaluated Aloe vera extract infused into anal fistula tracts in Wistar rats. Thirty male Wistar rats were submitted to anal fistula creation and after 30 days divided into three groups: Control, Carbopol (vehicle), and Aloe Vera. In the Aloe Vera group, a daily infusion of 0.3 mL of Carbopol plus Aloe Vera extract was performed through the external orifice of the fistula for 30 days. This study remains at the preclinical level, and its results cannot be directly applied to human fistula management.

Evidence strength: Preliminary to moderate for acute anal fissure (one small prospective double-blind trial); preclinical only for anal fistula. This is a promising result indicating that further comparative studies are justified. Mucopolysaccharides along with amino acids and zinc available in Aloe vera can lead to skin integrity, moisture retention, erythema reduction, and may help prevent skin ulcers — offering a plausible mechanistic basis for its observed effects.

5.2 Honey, Olive Oil, and Beeswax

Traditional Use

Honey has been used for millennia across diverse healing traditions — Egyptian, Greek, Ayurvedic, and traditional Islamic medicine — as a topical wound-healing agent due to its osmotic, antimicrobial, and humectant properties. Olive oil has been employed in Mediterranean and Middle Eastern traditional systems as an emollient and anti-inflammatory agent. Beeswax has been used in traditional pharmacy as a topical protective and healing base.

Scientific Evidence

A prospective pilot study (published in TheScientificWorldJOURNAL, 2006; PMID 17369999) by Al-Waili et al. evaluated a topical mixture of honey, olive oil, and beeswax in ratio 1:1:1 (v/v/v). Fifteen consecutive patients, including those presenting with anal fissure (5 patients) or first- to third-degree hemorrhoids, were treated with a 12-hour application of the natural mixture. Patients with anal fissure showed significant reduction in pain, bleeding, and itching after the treatment. No side effect was reported with use of the mixture. The authors concluded that a mixture of honey, olive oil, and beeswax is safe and clinically effective in the treatment of hemorrhoids and anal fissure, which paves the way for further randomized double-blind studies.

Evidence strength: Weak to preliminary — based on a single unblinded pilot study with a very small number of fissure patients (n=5). No powered randomized controlled trial has replicated these findings specifically in anal fissure patients.

5.3 Turmeric (Curcuma longa)

Traditional Use

Turmeric (Curcuma longa) is primarily used in the management of anal fistula and fissure due to its long-standing role in traditional medicine, particularly Ayurveda and other South Asian healing systems. Traditionally, turmeric is valued for its anti-inflammatory, antimicrobial, and wound-healing properties. It has been used both topically (as a paste) and orally (as a powder or in food) to support the healing of wounds, reduce local inflammation, and prevent infection.

Scientific Evidence

Scientific research has identified curcumin, the active compound in turmeric, as possessing anti-inflammatory and antioxidant properties. Several studies have shown that curcumin can modulate inflammatory pathways, promote wound healing, and inhibit the growth of certain bacteria. However, direct high-quality clinical evidence supporting the efficacy of turmeric specifically for anal fistula or fissure in humans is limited.

Evidence strength: Insufficient for this specific indication. The plausibility rests on preclinical mechanistic data on curcumin's general anti-inflammatory and wound-healing properties; no adequately powered clinical trial in anal fissure or fistula patients has been identified in the peer-reviewed literature.

5.4 Witch Hazel (Hamamelis virginiana)

Traditional Use

Witch hazel (Hamamelis virginiana) is traditionally used as a topical astringent for various skin and mucosal conditions, including hemorrhoids, minor skin irritations, and sometimes for anal fissures or fistulas. Its use in these anorectal conditions is based on its astringent, anti-inflammatory, and soothing properties, which are believed to help reduce local irritation, swelling, and discomfort. Witch hazel is commonly found in over-the-counter wipes and creams marketed for hemorrhoids, and by extension is sometimes used for fissures and fistulas due to similarity in symptoms such as pain, irritation, and inflammation.

Scientific Evidence

Scientific validation specifically for witch hazel's effectiveness in treating anal fissures or fistulas is limited. There are few, if any, high-quality clinical trials directly assessing its benefits for these specific conditions.

Evidence strength: Insufficient for this specific indication. Witch hazel's use in this context remains largely empirical and tradition-based.

5.5 Calendula (Calendula officinalis)

Traditional Use

Calendula has been used in European herbal traditions as a topical wound-healing and anti-inflammatory plant, applied to minor wounds, ulcers, and mucosal irritations. Its use in anorectal conditions follows this general wound-care tradition.

Scientific Evidence

A publication indexed in PubMed (PMID 22856483) is titled "Role of Calendula extract in treatment of anal fissures," indicating that investigative work exists in this specific area. However, details of study design, populations, and outcomes from this reference were not fully retrievable in this review. The effects of clove oil topical cream, Aloe vera topical cream, and a mixture of honey, olive oil, and beeswax on fissure in ano were interpreted as significantly positive in separate studies — with Calendula referenced alongside these as a plant studied in this domain.

Evidence strength: Preliminary and insufficient to draw conclusions based on currently retrievable peer-reviewed evidence in this specific condition.

5.6 Traditional Persian Medicine (Razi/Rhazes and Ibn Sina/Avicenna)

A 2017 peer-reviewed review (published in Journal of Evidence-Based Complementary & Alternative Medicine; PMC5871188) systematically examined the natural treatments recommended for anal fissure by the medieval Persian scholars Razi (865–925 CE) and Ibn Sina (980–1037 CE). Management of anal fissure according to Razi's and Ibn Sina's practices is done based on three interventions: lifestyle modifications, drug treatments, and manual procedures.

These remedies showed their effectiveness on fissure in ano via several mechanisms of action including anti-inflammatory, analgesic, wound healing, and laxative effects. Most of these natural remedies exerted their effect through more than one of the mentioned mechanisms. Specific plants listed from Razi and Ibn Sina include Allium cepa (onion), Althaea officinalis (marshmallow), Malva sylvestris (common mallow), Trigonella foenum-graecum (fenugreek), and Vitex agnus-castus, many of which contain flavonoid compounds that can be responsible for their anti-inflammatory effects.

Critically, almost all remedies suggested by Razi and Ibn Sina have shown their effects on fissure in ano via several mechanisms of action in many in vitro and in vivo studies; still there is a lack of human studies on the subject. The authors noted that despite many pieces of in vitro and in vivo evidence, only one clinical trial and one case report were found to confirm the effectiveness of investigated remedies.

5.7 Clove Oil (Syzygium aromaticum)

Traditional Use and Scientific Evidence

Clove oil has long been used in traditional medicine as a topical analgesic and antimicrobial agent. The effects of clove oil topical cream on fissure in ano were interpreted as significantly positive in separate studies, according to the PMC review of traditional Persian medicine. However, data from adequately powered randomized controlled trials in humans with anal fissure is not presently available in the peer-reviewed record.

Evidence strength: Preliminary — limited to small studies and preclinical data.

6. Lifestyle Factors

Sitz Baths

Warm sitz baths are among the most consistently recommended non-pharmacological measures across all major international guidelines. All four major international clinical guidelines (WSES/AAST, ACG, ACPGBI, ASCRS) recommend dietary fiber, stool softeners, hydration, and sitz baths for acute fissures. The proposed mechanism is that warm water immersion promotes local vasodilation and relaxation of the anal sphincter, potentially increasing anodermal blood flow and relieving ischemia. However, there is no strong evidence that sitz baths reduce pain or accelerate fissure or wound healing in controlled trial settings.

Bowel Habits and Straining

Avoidance of prolonged straining during defecation is emphasized across clinical guidance as a key preventive and supportive behavioral factor. To prevent and stop the progression of hemorrhoids and related anorectal conditions, adhering to the "TONE" strategy (T: Three minutes at defecation; O: Once-daily defecation; N: No excessive straining during passing motions or compulsive defecation; E: Enough fiber) is recommended.

Physical Activity, Sleep, and Stress

Individuals who are at higher risk for benign anorectal disorders or who are already suffering from such conditions may benefit from regular physical activity, good sleep hygiene, smoking cessation, and stress management strategies.

Nutritional Status and Wound Healing

Nutritional status more broadly affects the capacity for anorectal wound healing. Malnutrition was associated with increased postoperative complications and infections, whereas preoperative nutritional support correlated with reduced hospital stays and complications in a narrative review covering nutritional factors and surgical outcomes. Wounds undergo three healing phases: inflammatory, proliferative, and remodeling. The inflammatory phase involves clotting and cleaning the wound. The proliferative phase builds the wound bed through tissue growth. In the remodeling phase, collagen strength increases. Proper nutrition is crucial throughout.

Smoking and Metabolic Factors

Potential risk factors such as diabetes, smoking, fistula complexity, and surgical techniques have been suggested in individual studies as contributors to delayed wound healing after anal fistula surgery. Tight glycemic control is recognized in the wound-healing literature as important, given that uncontrolled hyperglycemia is known to impede fibroblast and endothelial cell functions, particularly in patients with diabetes.

References

• StatPearls: Anal Fissures — NCBI Bookshelf
• Medscape: Anal Fissure — Practice Essentials, Anatomy, Pathophysiology
• Medscape: Anal Fistulas and Fissures — Background, Pathophysiology, Epidemiology
• Heitland W. Perianal fistula and anal fissure. Chirurg. 2012;83(12):1033–9. PubMed PMID: 23179514
• BMJ Clinical Evidence: Anal fissure (chronic). PMC4229958
• Meta-analysis: Risk Factors for Recurrence after Anal Fistula Surgery. Int J Surg. 2019. PubMed PMID: 31400504
• Factors Increasing the Risk of Recurrence in Fistula-in-ano. PMC6505737
• Risk Factors for Delayed Wound Healing after Anal Fistula Surgery: Protocol of a Meta-analytic Study. PLOS One. 2025
• Treatment of Acute and Chronic Anal Fissures: A Comparative Analysis of International Guidelines. ResearchGate. 2025
• L-Arginine is a feasible supplement to heal chronic anal fissure via reducing internal anal sphincter pressure: a randomized clinical trial study. Amino Acids. 2023. PMC9713143
• Treatment of chronic anal fissure by application of L-arginine gel: a phase II study in 15 patients. Dis Colon Rectum. 2005. PubMed PMID: 15747070
• Exploring the therapeutic potential of L-arginine in chronic anal fissure management: a comprehensive review. Amino Acids. 2025. Springer
• Rahmani N et al. Effects of Aloe vera cream on chronic anal fissure pain, wound healing and hemorrhaging upon defection: a prospective double blind clinical trial. Eur Rev Med Pharmacol Sci. 2014;18(7):1078–1084
• The Effect of Aloe Vera Clinical Trials on Prevention and Healing of Skin Wound: A Systematic Review. PMC6330525
• Effectiveness of the Aloe Vera extract in the treatment of fistula-in-ano (animal study). Revista do Colégio Brasileiro de Cirurgiões. 2019. ScienceDirect
• Al-Waili NS et al. The Safety and Efficacy of a Mixture of Honey, Olive Oil, and Beeswax for the Management of Hemorrhoids and Anal Fissure: A Pilot Study. TheScientificWorldJOURNAL. 2006. PMC5944183
• Derakhshan AR. Natural Treatments for Fissure in Ano Used by Traditional Persian Scholars, Razi (Rhazes) and Ibn Sina (Avicenna). J Evid Based Complement Altern Med. 2017. PMC5871188
• Role of Calendula extract in treatment of anal fissures. PubMed PMID: 22856483
• Lifestyle Modifications and Dietary Factors versus Surgery in Benign Anorectal Conditions; Hemorrhoids, Fissures, and Fistulas. PMC10349156
• Nutrition in wound healing: investigation of the molecular mechanisms, a narrative review. PubMed PMID: 31600106
• The Roles of Micronutrition and Nutraceuticals in Enhancing Wound Healing and Tissue Regeneration: A Systematic Review. PMC12430280
• Impact of nutrition on skin wound healing and aesthetic outcomes: A comprehensive narrative review. PMC10874171
• Role of nutrition in wound healing and nutritional recommendations: a narrative review. Ann Clin Nutr Metab. 2023
• PathologyOutlines.com: Anal Fissure — Definition, Pathophysiology, Clinical Features
• Risk factors for anal fistula: a case-control study. PubMed PMID: 24452294