What Is Rectal Ejaculation? A Medical Explanation

Rectal ejaculation is exactly what the name suggests: semen exits through the rectum instead of, or in addition to, the urethra during orgasm. It is a rare clinical phenomenon, not a normal anatomical variant, and it almost always signals an abnormal connection, called a fistula, between the reproductive or urinary tract and the rectum. The condition has been documented in only a small number of published cases, but each one traces back to a recognizable set of causes, from cancer treatment to inflammatory bowel disease to congenital malformations present from birth.

The Underlying Mechanism

Under normal circumstances, semen travels from the seminal vesicles and prostate through the ejaculatory ducts, enters the urethra, and exits the body at the tip of the penis. For semen to end up in the rectum, there has to be a physical passage connecting some part of that tract to the rectal wall. That passage is a rectourethral fistula (or, less commonly, a fistula between the seminal vesicles or ejaculatory ducts and the rectum directly). Think of it as a tunnel that should not exist, bored through tissue that normally keeps the urinary-reproductive system completely separate from the gastrointestinal system.

When ejaculation occurs and pressure builds in the urethra and ejaculatory ducts, semen follows the path of least resistance. If a fistula is present, some or all of that ejaculate can be diverted into the rectum. One early documented case involved a man whose gradual loss of normal ejaculation was eventually explained by a fistulous connection between the ejaculatory duct area and the rectum; microscopic analysis of the rectal discharge confirmed the presence of semen.¹

What Causes These Fistulas

Rectal ejaculation does not happen out of nowhere. Something has to create that abnormal tunnel. The causes fall into three broad categories, and prostate cancer treatment is the most common one reported in the medical literature.

Prostate Cancer Treatment

Surgery and energy-based therapies for prostate cancer are the leading cause of acquired rectourethral fistulas in adults. The prostate sits directly in front of the rectum, separated by only a thin layer of tissue. When surgeons remove the prostate (radical prostatectomy) or destroy cancerous tissue with radiation, cryotherapy, or focused ultrasound, that thin barrier can break down. A multi-institutional study of over 200 men who needed fistula repair found that roughly half developed the fistula after radical prostatectomy alone, while the other half developed it after some form of energy ablation therapy.²

High-intensity focused ultrasound (HIFU), a newer minimally invasive treatment for localized prostate cancer, also carries this risk. In one series of patients treated with HIFU, about 2% developed a rectourethral fistula, typically within four weeks of the procedure. The risk climbed steeply with repeat sessions, reaching nearly 14% after a second HIFU treatment.³ That sharp jump likely reflects the cumulative damage to the already-weakened tissue plane between the prostate bed and the rectal wall.

Inflammatory Bowel Disease

Crohn’s disease is notorious for causing fistulas throughout the gastrointestinal tract. When the inflammation tunnels through the bowel wall, it can create connections to the skin, the bladder, the vagina, or, less commonly, the urethra and reproductive structures. A published case report on rectal ejaculation specifically noted that fistulous rectal connections with the ejaculatory duct or seminal vesicles have been documented in the context of inflammatory bowel disease, alongside surgical treatment for malignancy, as a recognized cause.⁴ While Crohn’s-related fistulas more commonly affect the vaginal or perianal areas in women, they can form between the rectum and the male urogenital system as well.⁵

Congenital Malformations

Some people are born with abnormal connections between the rectum and the urethra. These congenital rectourethral fistulas are typically identified and repaired in infancy as part of the broader management of anorectal malformations. In rare instances, however, a small fistula goes undetected until adulthood, when it finally produces symptoms. One such case involved a man who presented with infertility caused by rectal ejaculation; the fistula turned out to be congenital, having never been diagnosed in childhood.⁶

Separately, there are rare congenital anomalies where the ejaculatory ducts themselves open in the wrong location. A literature review identified 24 patients with ectopic ejaculatory ducts, with the ducts most commonly opening into a midline cyst, and in isolated cases, into the bladder trigone or bladder neck.⁷ These anomalies redirect semen to an abnormal destination, though they typically route it into the bladder rather than the rectum.

What It Feels Like and How It Is Noticed

Men with rectal ejaculation often do not realize what is happening right away. The earliest symptom may simply be a decline in ejaculate volume or the gradual onset of “dry” orgasms, where climax occurs but little or no semen comes out of the penis. At some point, a man may notice a mucus-like or milky discharge from the rectum during or after sexual activity. In the early documented case of a man with prostatic carcinoma, the initial presentation was precisely this pattern: a gradual inability to ejaculate normally, followed by the complaint that ejaculation seemed to be happening through the rectum.¹

If the fistula is large enough to allow two-way traffic, there may also be urinary symptoms. Urine can leak into the rectum (producing watery rectal discharge), or fecal material and gas can enter the urinary tract (causing foul-smelling urine, recurrent urinary infections, or the passage of gas through the urethra during urination). These overlapping symptoms sometimes make rectal ejaculation a secondary discovery, noticed only after the more disruptive urinary or fecal symptoms prompt an investigation.

How Doctors Confirm the Diagnosis

When a fistula is suspected, clinicians have several imaging and endoscopic tools to locate it and assess its size. Cystoscopy (a camera passed into the bladder through the urethra) and rectoscopy (a camera in the rectum) can sometimes visualize the fistula opening directly. Cross-sectional imaging, including CT and MRI, adds important detail about the surrounding tissue, any abscesses, and the fistula’s exact course through the tissue planes. MRI tends to be more useful for complex or recurrent fistulas because it shows soft-tissue anatomy in finer detail. In some cases, a contrast dye study (where dye is introduced into the bladder or urethra and tracked on fluoroscopy) can demonstrate the abnormal connection in real time.

When the presenting complaint is specifically rectal ejaculation, microscopic analysis of the rectal discharge can confirm the presence of sperm, settling the question of whether semen is truly exiting through the rectum rather than some other fluid mimicking it.

Treatment and Repair

Rectourethral fistulas rarely close on their own. While conservative management, including urinary diversion with a catheter and temporary fecal diversion with a colostomy, is sometimes tried first, most patients ultimately need surgery.⁸ More than 40 different surgical approaches have been described in the literature, a reflection of the fact that no single technique dominates. The choice depends on the fistula’s size, location, and cause, as well as whether the patient has had prior radiation (which impairs tissue healing).

One of the most commonly used approaches for complex or recurrent fistulas involves bringing in healthy tissue from elsewhere in the body to fill the gap. A muscle called the gracilis, which runs along the inner thigh, is frequently harvested on its blood supply and tunneled into the perineum to sit between the repaired rectal and urethral walls. This interposes a layer of well-vascularized tissue between the two suture lines, reducing the chance that the fistula reopens.⁹ The perineal approach, meaning surgery performed through the area between the scrotum and the anus, is the most common access route for these repairs.¹⁰

Simpler fistulas, particularly small ones that developed after a single surgical procedure and have not been irradiated, may be amenable to direct repair without muscle flap interposition. In those cases, the fistula tract is excised, and the rectal and urethral defects are closed in layers with the body’s own local tissue providing the barrier.¹¹ The decision to add a gracilis flap often comes down to how much the surrounding tissue has been compromised by radiation, infection, or previous failed repairs.

Impact on Fertility and Sexual Function

If semen is being routed through the rectum, it is obviously not reaching a partner, which makes natural conception impossible for as long as the fistula persists. Infertility may in fact be the presenting complaint that leads to the diagnosis, as happened in the reported congenital case mentioned earlier.⁶ Even after surgical repair, fertility may not automatically bounce back. A study examining long-term outcomes in men who had rectourethral fistula repair for congenital anorectal malformations found that while erectile function was generally preserved, about 15% of the men with a rectourethral fistula history had absent ejaculations or azoospermia (no sperm in the ejaculate).¹²

The same study noted that while the ability to have orgasms was preserved at rates similar to those in people without the condition, the age at which these men first had sexual intercourse was significantly later than in the control group. That delay likely reflects a combination of medical history, body image concerns, and the practical challenges of living with a condition that affects such an intimate function during formative years.

Recovery and Quality of Life After Surgery

Repair of a rectourethral fistula is major surgery, and the recovery period is substantial. Patients typically live with a temporary colostomy (to divert stool away from the repair site) and a urinary catheter for weeks to months while the tissues heal. Even after successful closure, long-term follow-up data paint a mixed picture.

In one series that tracked patients for an average of nearly four years after repair, 80% said the surgery had a positive impact on their life, which is encouraging. At the same time, about half reported perineal pain at long-term follow-up, roughly 40% had problems related to the gracilis muscle flap at the harvest or implant site, and 80% experienced some degree of urinary incontinence, most of it mild and occasional.¹³ About one in five reported being unable to do the things they wanted in daily life. These numbers reflect the reality that while the fistula itself can be closed, the surgery and the underlying condition it arose from often leave lasting marks on continence, comfort, and daily function.

The high rate of residual urinary symptoms is partly a consequence of the conditions that caused the fistula in the first place. Many of these men had already undergone radical prostatectomy or radiation therapy before developing the fistula, and those treatments carry their own long-term effects on the urinary sphincter and bladder. The fistula repair adds another layer of surgical disruption to an already compromised area.

Why the Condition Is So Rarely Discussed

Rectal ejaculation sits at an intersection of anatomy that most people find difficult to talk about. The combination of sexual function, rectal symptoms, and cancer treatment creates a topic that patients are understandably reluctant to bring up, even with their doctors. Published case reports have described it as an “extremely rare” presentation, and the medical literature itself is thin, consisting primarily of individual case reports and small case series rather than large studies.⁴

That rarity in the literature may not perfectly reflect reality. A man who has undergone prostate cancer treatment and notices diminished ejaculate volume might not think to mention a small amount of rectal discharge, or might attribute it to something else entirely. Clinicians who are not specifically asking about ejaculatory changes after prostate surgery may miss the symptom as well. The condition likely exists in a modest gray zone between “genuinely very rare” and “underreported because nobody wants to talk about it.”

When to Seek Medical Attention

Any new rectal discharge that coincides with sexual activity warrants a conversation with a urologist, particularly if you have a history of prostate cancer treatment, pelvic radiation, Crohn’s disease, or previous pelvic surgery. The same applies if you notice a significant drop in ejaculate volume without an obvious explanation, or if you develop recurrent urinary tract infections alongside changes in ejaculatory function.

If you were born with an anorectal malformation that was repaired in childhood and are now experiencing ejaculatory difficulties or infertility, it is worth revisiting the possibility that a residual or recurrent fistula may be contributing. Congenital fistulas that were thought to be fully repaired can sometimes leave behind a small tract that only becomes clinically relevant once adult sexual function is established.

The diagnostic workup is straightforward once the possibility is raised, and treatment options exist even for complex fistulas. Getting the right diagnosis is the hardest part, and that starts with being willing to describe the symptom accurately to a doctor who knows what to look for.