Swollen hemorrhoids can partially block the passage of stool, though a complete obstruction from hemorrhoids alone is rare. Prolapsing internal hemorrhoids, in particular, can bulge into the anal canal enough to interfere mechanically with defecation, creating a sensation of incomplete emptying or making it difficult to push stool through. The relationship between hemorrhoids and difficulty passing stool is more tangled than most people realize, involving not just physical bulk but also elevated pressure in the anal canal and a self-reinforcing cycle of straining.
How Hemorrhoids Physically Get in the Way
Internal hemorrhoids that have progressed to the point of prolapsing, meaning they bulge out of the anal canal during a bowel movement, can act as a partial physical barrier. A gastroenterology review published in Gastroenterology describes the mechanism plainly: prolapsing hemorrhoids may partially obstruct defecation and cause soilage from the passage of fecal material, mucus, or blood.1Gastroenterology. Medical management of fecal incontinence That partial obstruction is the key phrase. It is not that hemorrhoids seal the canal shut like a cork. Instead, the swollen tissue narrows the available space, so stool has to squeeze past engorged cushions. For small, soft stools this may go unnoticed, but for firmer or larger stools the resistance becomes real.
External hemorrhoids, which sit just outside the anal opening, create a different kind of problem. When they become engorged or thrombosed (filled with a blood clot), they cause significant pain. A review in JAMA notes that external hemorrhoids cause rectal pain when engorged or thrombosed, and the recommended first-line approach for all hemorrhoidal disease is increasing dietary fiber and water intake while avoiding straining.2JAMA. Hemorrhoidal Disease: A Review Pain itself becomes a barrier to bowel movements because you instinctively tighten the sphincter and hold back, which keeps stool in the rectum longer, makes it harder and drier, and sets the stage for even more straining the next time around.
The Feedback Loop Between Hemorrhoids and Constipation
Hemorrhoids and constipation feed off each other in a cycle that can be surprisingly hard to break. You might assume one clearly causes the other, but the relationship runs in both directions. Constipation leads to straining, which engorges hemorrhoidal tissue and makes it swell. That swelling then narrows the anal canal and increases pain, which makes the next bowel movement more difficult, which causes more straining, and so on.
A study of patients undergoing colonoscopy found that constipation scores were significantly higher in people who had hemorrhoids compared to those without them. Specifically, “painful evacuation effort” and “assistance for defecation” (needing laxatives, digital help, or enemas) were both significantly correlated with having hemorrhoids.3PubMed. Haemorrhoids, constipation and faecal incontinence: is there any relationship? That finding is telling because it shows the problem is not just about the hemorrhoid tissue being in the way. It is also about how hemorrhoids change the experience of defecation enough to drive compensatory behaviors like straining harder, sitting on the toilet longer, and resorting to manual or pharmaceutical help.
A systematic review and meta-analysis confirmed this pattern more broadly, finding that functional constipation and dyssynergic defecation (where the muscles involved in pushing stool out do not coordinate properly) are both more common in people with hemorrhoids than in healthy controls.4European Journal of Gastroenterology & Hepatology. Functional constipation in patients with hemorrhoids: a systematic review and meta-analysis The picture that emerges is one where hemorrhoids do not just passively sit there. They actively change how you defecate, and those changes make the hemorrhoids worse.
Why Anal Pressure Matters More Than You’d Think
One of the less obvious ways hemorrhoids interfere with bowel movements is through elevated resting pressure in the anal canal. The anal sphincter is supposed to relax when you bear down to pass stool, but in people with symptomatic hemorrhoids the baseline pressure is already higher than normal, meaning the sphincter has to relax further to allow stool through.
Multiple studies have measured this directly using manometry, a technique that gauges pressure inside the anal canal. One early study found that patients with symptomatic hemorrhoids had significantly higher maximal basal pressure and maximal voluntary contraction pressure compared to controls.5PubMed. Anal manometric findings in symptomatic hemorrhoids A separate study put numbers on the difference: the average maximal basal pressure was about 85 mmHg in hemorrhoid patients versus roughly 71 mmHg in controls, and contraction pressures were similarly elevated at about 159 mmHg versus 133 mmHg.6PubMed. Anal manometric studies in hemorrhoids and anal fissures These differences are statistically significant and clinically meaningful, because that extra resting pressure means the canal is tighter before you even start trying to go.
The systematic review mentioned earlier confirmed that these elevated anal pressures persist in hemorrhoid patients across all the manometric studies it examined, and that the pressures remained significantly elevated even after office treatments like rubber band ligation.4European Journal of Gastroenterology & Hepatology. Functional constipation in patients with hemorrhoids: a systematic review and meta-analysis That last detail is worth flagging: even after a common outpatient procedure, the heightened pressure does not fully normalize, which helps explain why some people continue to feel like something is blocking them even after treatment.
What You Can Do When Hemorrhoids Make It Hard to Go
The first-line advice is consistent across virtually every clinical guideline: eat more fiber, drink more water, and stop straining. That sounds almost too simple, but it directly addresses the vicious cycle. Softer, bulkier stool passes with less force, which means less engorgement of hemorrhoidal tissue, less pain, and less reason to bear down next time. The JAMA review identifies this triad of increased dietary fiber, increased water, and avoidance of straining as the starting point for managing all types of hemorrhoidal disease.2JAMA. Hemorrhoidal Disease: A Review
Over-the-counter treatments can help with acute swelling. Some physicians recommend flavonoid-based oral medications (sold under various brand names depending on the country) to reduce hemorrhoidal edema. A meta-analysis of these flavonoid preparations found that in some trials, clinical improvement in edema was dramatically better than placebo after a week of treatment, though other trials found no significant difference at the same time point.7PubMed Central. Micronized Purified Flavonoid Fraction in Hemorrhoid Disease: A Systematic Review and Meta-Analysis The inconsistency across studies is worth knowing about: flavonoids seem to help some people in acute flares but should not be relied on as the sole approach.
Warm sitz baths (sitting in a few inches of warm water for 10 to 15 minutes) can relieve pain and may help the sphincter relax, indirectly making it easier to have a bowel movement. Topical creams containing lidocaine or hydrocortisone can reduce pain and inflammation enough to break the pain-avoidance cycle, where fear of pain keeps you from going and the resulting backup makes the next attempt worse.
How Toilet Posture Changes the Equation
The angle at which you sit on the toilet has a surprisingly large effect on how easy it is to pass stool, and this becomes even more relevant when hemorrhoids are narrowing the canal. When you sit upright on a standard Western toilet, the anorectal angle stays partially kinked, meaning your rectum does not align straight with the anal canal. In a squatting position, that angle straightens, reducing resistance.
Research comparing defecation posture found that squatting can cut defecation time dramatically, to roughly a minute compared to anywhere from four to fifteen minutes in a standard sitting position, while also reducing straining episodes.8PubMed Central. Health promotion and prevention of bowel disorders through toilet designs: A myth or reality? You do not need to replace your toilet: a simple footstool that elevates your knees above your hips mimics the squatting angle and can make a meaningful difference. For someone whose hemorrhoids are contributing to a feeling of blockage, this postural change alone can reduce the amount of pressure needed to evacuate and potentially reduce further swelling.
Office Procedures for Hemorrhoids That Keep Getting in the Way
When lifestyle changes are not enough, several outpatient procedures can shrink hemorrhoidal tissue without requiring surgery. The most common is rubber band ligation, where a small elastic band is placed at the base of an internal hemorrhoid to cut off its blood supply, causing it to shrink and fall off within a few days. In a study of 50 patients who underwent the procedure, half reported no discomfort afterward, and about 44 percent had only mild pain managed with over-the-counter painkillers. Around 90 percent of patients were satisfied and said they would choose the procedure again.9PubMed Central. Rubber Band Ligation: A New Treatment Option for External Hemorrhoids
Other in-office options include infrared coagulation and sclerotherapy (injecting a solution that shrinks the hemorrhoid). These are typically used for smaller, earlier-grade internal hemorrhoids. None of these procedures are designed to address the underlying constipation or elevated anal pressure, though, so they work best when combined with the dietary and behavioral changes described above.
For more advanced hemorrhoids, surgical options like stapled hemorrhoidopexy exist. One comparative study found that a modified stapled procedure had a lower recurrence rate than the standard version (about 9 percent versus 19 percent), though it came with a higher rate of a lingering sensation of needing to go even when the rectum was empty.10Baishideng Publishing Group Inc. Modified procedure for prolapse and hemorrhoids: Lower recurrence, higher satisfaction That sensation, called rectal tenesmus, is worth knowing about because it mimics the very symptom that brought many patients in: feeling like something is blocking them from completing a bowel movement. In other words, one surgical approach trades the physical obstruction from hemorrhoids for a nerve-related sensation that feels similar, at least temporarily.
When the Blockage Feeling Is Not Actually Hemorrhoids
One of the practical dangers of hemorrhoids is that they are so common people tend to attribute all rectal symptoms to them, including symptoms that deserve a closer look. If you feel like something is blocking your bowel movements, hemorrhoids are one possibility, but there are others that matter.
Rectal prolapse, where the rectal wall itself slides down into or through the anal canal, can feel a lot like prolapsing hemorrhoids but is a different condition with different treatment. Rectoceles (a bulging of the rectal wall into the vagina) can also create a sensation of incomplete evacuation and difficulty passing stool. Dyssynergic defecation, the coordination problem between abdominal pushing and pelvic floor relaxation, is another underdiagnosed cause of feeling blocked. As the earlier meta-analysis noted, dyssynergic defecation is more common in hemorrhoid patients, so the two conditions often overlap.4European Journal of Gastroenterology & Hepatology. Functional constipation in patients with hemorrhoids: a systematic review and meta-analysis
More concerning is the possibility that a growing tumor in the rectum or lower colon is causing the obstruction. Colorectal cancer can produce symptoms that are virtually indistinguishable from hemorrhoids: bleeding, a feeling of incomplete evacuation, changes in stool caliber. A study tracking patients who eventually received a colorectal cancer diagnosis found that those who had rectal bleeding actually delayed seeking care significantly longer than those without bleeding, with a median delay of 39 days versus 15 days. The researchers found that patients with rectal bleeding were more likely to have wondered whether their symptom could be cancer, yet paradoxically they waited longer before seeing a doctor.11PLOS ONE. Patient Delay in Colorectal Cancer Patients: Associations with Rectal Bleeding and Thoughts about Cancer The likely explanation is that people with rectal bleeding tell themselves it is “just hemorrhoids,” and the very familiarity of hemorrhoids as a benign diagnosis provides a false reassurance that delays investigation.
The practical takeaway is that if you have bleeding, a persistent feeling of obstruction, or a change in your bowel habits that does not improve with standard hemorrhoid treatment within a few weeks, you should see a doctor for an examination. No amount of self-diagnosis can safely distinguish a prolapsing hemorrhoid from something more serious without a physical exam and, in many cases, a colonoscopy.
Anal Stenosis After Hemorrhoid Surgery
There is an ironic complication that can develop after hemorrhoid surgery itself: anal stenosis, a narrowing of the anal canal caused by scar tissue replacing the removed or damaged tissue. This is a genuinely physical blockage, unlike the partial obstruction from hemorrhoids, and it makes passing stool painful and difficult.
Anal stenosis is uncommon but well-documented. One review noted that about 90 percent of anal stenosis cases are caused by overly aggressive hemorrhoidectomy, where too much tissue is removed and the resulting scar contracts the canal.12PubMed Central. Surgical treatment of anal stenosis A case series examining patients who developed this complication described it as “a narrowing of the anal canal” where “loose fibrous tissue replaces healthy tissue,” causing pain during defecation.13International Journal of Surgery Open. Repair of anal stenosis using a prolapse and hemorrhoids (PPH) stapler procedure: A case report with excellent results A separate surgical case series confirmed anal stenosis as a rare but serious outcome following hemorrhoid surgery and described various surgical techniques used to correct it.14PubMed Central. Surgical management of anal stenosis following hemorrhoid treatment: a single-center case series
The relevance here is that someone who has had hemorrhoid surgery in the past and now feels like their bowel movements are obstructed should consider whether stenosis, not recurrent hemorrhoids, is the problem. The treatment is different: severe stenosis typically requires a formal anoplasty, a procedure that brings in healthy tissue to widen the narrowed canal, rather than simply removing more hemorrhoidal tissue, which could make things worse.
If you had a hemorrhoidectomy and gradually noticed increasing difficulty passing stool, pencil-thin stools, or a sensation of something physically tight when you bear down, those are signs worth bringing to your surgeon. Stenosis tends to develop over weeks to months after surgery, so the timeline can help distinguish it from other causes.