Anal fissures and fiber: what TikTok skips over

What did @drsermedmezher actually say?

The creator described anal fissures as cuts caused by straining during bowel movements, noting they produce rectal bleeding that can look alarming when Googled. He said fissures "usually get better after a round of a week" with laxatives and medicated gel to reduce muscle spasm. He also flagged that chronic, recurring fissures might signal "quern's disease" (he means Crohn's disease) and advised viewers to get checked out if lifestyle changes aren't working. The core message: rectal bleeding from straining is probably not cancer, probably a fissure, and usually treatable at home.

That framing is broadly reasonable for a short-form video. The creator is a UK-based doctor and stays in his lane here. But a few specific claims deserve closer scrutiny, particularly the healing timeline and the Crohn's connection.

Does the science back this up?

Mostly, yes. Acute anal fissures do resolve with conservative management in the majority of cases, though "a week" is optimistic. The evidence puts it closer to six to eight weeks for full healing with first-line treatment. The rest holds up reasonably well.

A 2014 systematic review by Stewart et al. in the Cochrane Database of Systematic Reviews found that topical glyceryl trinitrate (a common medicated gel) healed acute fissures in roughly 50% of patients compared to 35% with placebo, with healing taking several weeks. A 2017 review by Gallo et al. in Techniques in Coloproctology confirmed that fiber supplementation and stool softeners reduce recurrence rates. The Crohn's disease link is real and clinically important: a 2019 study by Eglinton et al. in Inflammatory Bowel Diseases found perianal disease, including fissures, occurs in up to 36% of Crohn's patients and is often a presenting feature. So raising it here is appropriate, not alarmist.

What did they get wrong (or right)?

The one week healing claim is the main problem. It is probably wrong, and setting that expectation could cause patients to stop treatment too early or panic when they aren't healed in seven days.

What he got right: the reassurance that rectal bleeding from straining is not automatically cancer. Colorectal cancer fear is a documented barrier to people seeking care for benign anorectal symptoms (Jones et al., 2007, British Journal of General Practice). Normalizing the conversation matters. He also correctly identified that spasm of the internal anal sphincter perpetuates fissures, which is why topical antispasmodics work. The Crohn's flag is a legitimate clinical prompt that many creators skip entirely. Credit where it is due.

What he glossed over: not all rectal bleeding is a fissure. Hemorrhoids, inflammatory bowel disease, and, yes, colorectal malignancy can all present similarly. The video leans a little too hard on reassurance without the caveat that persistent or unexplained rectal bleeding always warrants a clinical assessment, not just dietary changes.

What should you actually know?

Anal fissures are common, painful, and usually benign, but rectal bleeding is not a symptom you self-diagnose via TikTok. Here is what the evidence actually supports.

• Acute fissures heal in most people with increased dietary fiber, adequate hydration, and stool softeners, but expect weeks, not days. Six to eight weeks is a realistic target (Mapel et al., 2014, American Journal of Gastroenterology).
• Topical treatments like glyceryl trinitrate or diltiazem gel reduce sphincter spasm and improve healing rates, but both carry side effects including headache. Talk to a clinician before starting them.
• Any rectal bleeding that is unexplained, persistent, or accompanied by weight loss, change in bowel habit, or abdominal pain needs a clinical evaluation. Do not assume fissure without a diagnosis.
• Crohn's-related fissures often look different: they may be multiple, off-midline, or poorly healing. A gastroenterologist should assess them.
• Straining is both a cause and a consequence. Treating the underlying constipation is not optional; it is the mechanism by which fissures recur.