Hematospermia demystified

An anxious colleague recently came into my office and closed the door. “I think I might have prostate cancer,” he said quietly. After a moment of stunned silence, I asked him about his prostate-specific antigen (PSA) level and whether he had had a biopsy. “I haven’t had a PSA test recently, and I’ve never had a biopsy,” he replied. “What makes you think that you might have prostate cancer?” I asked. “Well,” he said, “my wife and I had sex last night, and she noticed that there was blood in my semen.”

Few things alarm a man and his partner more than seeing bloody ejaculate, a condition called hematospermia, or hemospermia. It conjures fears of cancer or a sexually transmitted disease. While it’s true that hematospermia may indicate prostate cancer or another urologic disease, that’s usually not the case. In many instances, it has no apparent cause. Just as puzzling, the condition can be limited to a single episode or can occur repeatedly over several weeks or months before disappearing completely.

Doctors have been diagnosing hematospermia for centuries — even the Greek physician Hippocrates, who lived from around 460 to 377 B.C., described it. But the true prevalence of the condition remains a mystery. A busy urologist may see several patients a year with hematospermia, but it’s likely that far more cases go unnoticed by a man or his partner during intercourse. And some cases certainly go unreported by men who’d rather not find out what ails them.

Although health care professionals can’t quantify hematospermia’s prevalence, they have been increasingly able to ascribe the condition to a particular cause, thanks to better diagnostic techniques, advances in medical imaging, and some good old-fashioned sleuthing. From there, they can either prescribe medication or another treatment, or offer an anxious patient some much-needed reassurance that the condition will resolve on its own.

Among the culprits…

Historically, doctors linked hematospermia to sexual behavior. As the authors of an article in The Journal of Urology explain, patients were “warned about excessive overindulgence and prolonged sexual abstinence.” And as recently as a decade ago, most cases (up to 70% in some studies) were diagnosed as idiopathic, meaning that they had no obvious cause. The condition, researchers believed, was “benign and self-limited.” But in 2003, thanks to improved imaging techniques, a team of researchers classified only about 15% of cases as idiopathic. The rest of the cases were attributed to dozens of other factors that they grouped into six categories, as follows.

Inflammation and infection

Inflammation of any of the organs, glands, or ducts involved in the production or storage of seminal fluid can lead to hematospermia. These include the seminal vesicles, vas deferens, epididymis, prostate, and urethra (see Figure 1 below). Inflammation can be caused by irritation or trauma; stones or calcified deposits in the prostate, seminal vesicles, bladder, or urethra; and infections with viruses, bacteria, fungi, or parasites. Sexually transmitted diseases, such as herpes, gonorrhea, and chlamydia, have also been implicated in hematospermia.

Some studies have shown that inflammation and infection are the most common causes of hematospermia in younger men (the average age of hematospermia patients is 37) and up to 39% of cases over all.

Figure 1: Anatomy of hematospermia

Anatomy of hematospermia

Inflammation and infection, an obstruction, a tumor, vascular abnormalities, systemic factors, medical procedures, and trauma may cause bleeding that shows up in semen, a condition called hematospermia, or hemospermia. Any of the organs, glands, or ducts shown here may be the source of the bleeding, though the cause and source of the bleeding often can’t be determined. Note that only a portion of the vas deferens, which transports sperm from the epididymis to the seminal vesicles, is shown.


Obstructed ducts, such as the ejaculatory duct, and the formation of cysts in the prostate or seminal vesicles can cause hematospermia. When ducts are blocked, nearby blood vessels can dilate and rupture. An enlarged prostate, also called benign prostatic hyperplasia, pinches the urethra and can lead to hematospermia, too.


Benign polyps and malignant tumors of the prostate, testicles, epididymis, and seminal vesicles may cause hematospermia. Men whose sole symptom is hematospermia are more likely to have prostate cancer than men who don’t have blood in their semen, but the chances are slim. A Northwestern University study of 26,126 men who underwent prostate cancer screening proves the point: among all study participants, 6.5% were diagnosed with prostate cancer. Among those who complained of hematospermia, 13.7% were diagnosed with prostate cancer. (For more details, see “Hematospermia and prostate cancer,” below.) Even though the finding is statistically significant, keep in mind that more than 86% of men with hematospermia don’t have prostate cancer. One could argue, too, that these numbers may be elevated because a screening study like this is likely to attract men at greater-than-average risk of prostate cancer.

A review of other scientific articles found 33 tumors in 931 patients with hematospermia, or 3.5%, far fewer than in the Northwestern study. Of the 33 tumors that were identified, 25 were prostate tumors. The other eight tumors were found in the seminal vesicles, testicles, and epididymis.

Hematospermia and prostate cancer

Han M, Brannigan RE, Antenor JA, et al. Association of Hemospermia with Prostate Cancer. Journal of Urology 2004;172(6 Pt. 1):2189–92. PMID: 15538229.

Vascular abnormalities

Blood vessel abnormalities in the seminal vesicles, bladder, prostate, seminal vesicles, and spermatic cord (the vas deferens and its accompanying arteries, veins, nerves, and lymphatic vessels) may be the source of bleeding.

Systemic factors

Several diseases and disorders that affect the whole body have been linked to hematospermia. These include severe hypertension (high blood pressure), a bleeding disorder called hemophilia, leukemia, and chronic liver disease.

Trauma/medical procedures

Most cases of hematospermia are probably caused, unintentionally, by medical procedures. Transrectal ultrasound prostate biopsy (TRUS-PB), which removes bits of prostate tissue to check for cancer, provokes it. The reported incidence of hematospermia following a biopsy varies between 5.1% and 89%. A recent study by Miami researchers pegged the incidence of hematospermia following TRUS-PB at 84%. On average, hematospermia lasted three and a half weeks before resolving on its own. (For more details, see “Hematospermia and TRUS-PB,” below.)

Other medical procedures, including radiation therapy, brachytherapy, transurethral resection of the prostate (for BPH), and vasectomy can bring about hematospermia, as can testicular or perineal trauma, pelvic fracture, injury during sex, and prolonged sexual abstinence.

Admittedly, reading this long list of possible causes may do little to reassure a man with bloody semen. My colleague, for example, now not only worried that he had prostate cancer, but also that he had polyps, cysts, blocked ducts, and tuberculosis, too. But if you experience hematospermia, don’t let your mind run wild. (Remember that most cases can’t be attributed to a particular cause and resolve on their own without treatment.) Instead, schedule an appointment with your doctor or urologist. If a cause can be determined, it can be treated. If no cause can be found, you’ll probably breathe a bit easier.

Hematospermia and TRUS-PB

Manoharan M, Ayyathurai R, Nieder AM, Soloway MS. Hemospermia Following Transrectal Ultrasound-Guided Prostate Biopsy: A Prospective Study. Prostate Cancer and Prostatic Diseases 2007;10:283–87. PMID: 17310259.

Detective work

Your doctor or urologist will begin by taking a detailed medical history and asking questions about your symptoms: How and when did you notice blood in your semen? Have you had a single episode of hematospermia, or has the condition been persistent? Have you had any urologic tests or a prostate biopsy recently? Have you traveled to any areas where tuberculosis is common? What medications are you taking? Have you experienced other symptoms, such as fever, unexplained weight loss, urinary problems, or pain? He or she will also ask about sexual activity.

Next, your doctor will conduct a physical exam to rule out various conditions that can cause hematospermia. He or she will take your blood pressure and temperature, feel your abdomen, examine your genitals, and perform a digital rectal exam to feel for hard spots on the prostate gland and for cysts in the seminal vesicles.

In addition, you will have a blood test, urine analysis, and urine culture. If sexually transmitted diseases are suspected, your doctor may test for them. And if there’s a chance that the blood may have come from your partner, your doctor may suggest a condom test: ejaculate is collected in a condom and then examined for blood.

Just as there is little consensus about when, or even whether, a healthy man should have a PSA test, physicians don’t always agree about when or whether patients with hematospermia should have one. Some experts say it’s necessary only in patients over age 50 unless the patient has a family history of prostate cancer. Others, including me, recommend PSA testing in all hematospermia patients over age 40 because, as I noted, it can be a sign of prostate cancer. The incidence of prostate cancer in younger men is quite low — according to the National Cancer Institute, only 0.6% of cases are diagnosed in men age 44 or younger. So, in my opinion, PSA testing before 40 probably isn’t necessary unless you have other symptoms. In an older man with a borderline-high PSA score, I would consider ordering a prostate biopsy.

Men who have persistent hematospermia, blood in the urine, or other symptoms, or who are over age 40 may have a transrectal ultrasound (TRUS) to look for abnormalities in the prostate, seminal vesicles, and other tissues. During this procedure, the doctor inserts an ultrasound probe into the rectum (see Figure 2 below). The probe emits sound waves and then “listens” for echoes as the waves bounce back off surrounding tissues (the prostate, for example).

Figure 2: Transrectal ultrasound

Transrectal ultrasound

During a transrectal ultrasound, an ultrasound probe is inserted into the rectum. The probe emits sound waves that bounce back off surrounding tissues. Depending on the strength, pitch, and direction of the reflected sound waves, a computer can create pictures of the internal anatomy.

Based on the strength, pitch, and direction of the reflected waves, a computer creates pictures of the internal anatomy (see Figure 3 below). Several studies have shown that TRUS effectively pinpoints usually benign abnormalities that can lead to hematospermia in 74% to 95% of patients. Among the findings: enlarged seminal vesicles; stones in the seminal vesicles, prostate, or ejaculatory duct; cysts; and BPH. Interestingly, no cancers were detected in these studies. Because it is so effective and minimally invasive, TRUS is the first type of imaging that should be performed.

Depending on what information TRUS yields, your doctor may recommend two other procedures: magnetic resonance imaging (MRI) and cystoscopy. Unlike TRUS, MRI can reveal bleeding in the seminal vesicles or prostate. Cystoscopy allows your doctor to examine the inside of the bladder and urethra, areas that may not show up well on MRI and TRUS, with a thin, lighted instrument called a cystoscope.

Figure 3: A transrectal ultrasound image

A transrectal ultrasound image

A trained eye can spot structures such as the prostate, bladder, and rectum on a computer-generated transrectal ultrasound image. In some cases, cancerous lesions may be apparent.

Case closed

The treatment for hematospermia, obviously, depends on the cause. Infection, for example, should be treated with antibiotics. Bleeding in the seminal vesicles, urethra, and prostate can be halted with an electric current. Any systemic problems, such as high blood pressure, should be controlled or treated. And if the amount of blood in the semen is slight, or in cases where there is only one or two episodes of hematospermia, a wait-and-see approach might be best. However, if hematospermia returns, check back with your doctor. Some doctors have found that treating chronic hematospermia with finasteride or dutasteride solves the problem, though no clinical trials have proven the medications to be effective in hematospermia patients. Others may prescribe antibiotics if they suspect asymptomatic prostatitis.

As for my colleague, I am happy to report that he is fine. He had several tests, including a TRUS, but we weren’t able to identify the cause of the bleeding. He did mention that he and his wife hadn’t had sex in quite a while, so the spotting that he saw may well have come from overly full seminal vesicles. Regardless, he hasn’t experienced any more episodes of hematospermia.

While hematospermia can certainly be frightening, it is a benign disorder in most patients. A quick visit with your doctor will probably reassure you that hematospermia is little more than a case of smoke without the fire.

Originally published March 2009; last updated April 22, 2011.


Had first episode heamatospermia during an infection nearly 2 years ago. Had xrays / cystoscopy / ultra sound testicles. Informed that it must have been infection. No problems for 15 months then unfortunately 3 times this year. Approx 3 month gaps. Now stating 2 weeks of antibiotics.

Charles Hooper

Thanks so much for the helpful information.

I have had recurring hematospermia for 3 years, am 60 y/o, have seen a urologist and had an MRI and a couple rounds of abx.

The first time I had hematospermia a combination of abx and prostate squeezing (yikes!) indicated infection and resolved it. Later bouts were not due to any apparent infection and the MD essentially said he had no idea.

Now I am having a strong smelling urine for over three weeks and am rushing to my PCP. My question is, do you know any urologists who specialize in hematospermia?

Perhaps I should have gotten another opinion previously, but now I’m alarmed.Thanks very much if you can reply. If not, I understand and again thank you for the information.


I am 35 y/o, experiencing blood clots in semen for the last 4 months n it is continued. I had n Mri ,cystocoy was done ‘ they hv found slight enlargement of left seminal vesicle wid different fluid levels with some calci on prostate. In cystoscopy they found little erosion on prostate .
I was takin cipro then leflox wid max flow but no gain still havin blood clots.
Really worried now.
Doc says it jus coz of inflamation of sem vesicles. They cant do much abt it ‘ But what is the treatment?
Pls help.


Thank you for the information Im 19 and I guess I had some Vigorous sex which caused it. Im waiting and staying away from ejaculation for a couple weeks to see if it goes away.


I am a 60yo who hasn’t had sex in about 2 years. I have masturbated on occasion, but not anywhere near as often as I would have sex, if I were married. I have suffered a few bouts of hematospermia over the last 6 months – mostly caramel colored semen. Today I had a first time experience with frank blood in the semen. There were discrete spots – large enough to be seen as spots – as large as grains of rice, and very discrete. No sensation of pain. Just the blood.

I know, go see a doctor. But do you have any gut feelings?


i am 36 year old male. initially there was blood in urine at start of micturation followed by brown colored semen. i took 2 week course of ciprofloxacin and doxycycline for 1 and half month .there is stil brown color semen and frequency of micturation . plz tell me treatment


Why is there nothing to be found anywhere on the internet about a cure for blood in seman? I have had this problem for 3 years now. I have been thru every test and the urologist says nothing wrong but some calculi in prostate and he cant help me any further. what about massage of transrectal heat rotating magnetic field? An article says it works but then the trail goes dead – cant find anything more. do i just have to live with this the rest of my life until it kills me?


I first noticed my haematospermia in November 2013,at first it was intermittent though more recently has become the norm with discoloration at first ranging from pinkish to brownish red. Its now quite fluidic and watery and comprised only of pre-ejaculate with a complete absence of semen. There is no pain and have had psa test and ultrasound which revealed nothing obvious. Next port of call is a cystoscopy.I’m deeply distressed by both loss of libido and a normal sex life.


I am an 85-yr old male. Recently I have seen a strong whitish ejaculate followed by a slightly weaker light brownish linear discharge. No other symptoms. Urination greatly improved after ejaculation. I have no yet reported this to my family doctor.
Recurrent prostatitis years ago, treated with antibiotics, has not returned.
Otherwise, I have frequent bleeding trouble(gums) possibly related to 3.1 Protime from daily dose of 2.5 mg warfarin prescribed on account of atrial flutter. No flutter symptoms in about 10 years. Minor non-clot stroke experienced months ago. A CABG 4X 12 years ago.
Diagnosed with DDD a few years ago, weight lifting limited.
BP usually under 120/80(systolic sometimes under 90)and HR either about 75 or about 45. Height 5’9″ down from 6,” weight about 160 down about 27 from all time high.

jay alcantara

sir please help me for the treatment of my hematospermia.. im 43 years old. and my problem started 3 months ago.. i have a lot of blood in my sperm.but it is not painful.i dont have any blood in my urine only in my sperm.. how to cure this problem please help me.. tnx in advance


Guys. My bout with it was BAD. 99% blood came out when I ejacualted for 6 months. I figured mine out. High intake of red meats. I assume that the uric acids built up way to much and it started crystallizing down there. Lay off the red meats and control your intake of coffee, sugars and dairy. Drink tons of water too. Simple. Rest & heal easy.


I am 50y/o. I had never taken medication in my life untill three weeks ago when I was prescribed a triple dose for ulcers. After the 7 day course i noticed blood in my poo just once. Today I notice my ejaculation is 90% blood. I am scared and i now imagining pain in my pipes


“BAD?” You wanna know “bad?”
I was 21 when I had my initial episode. I’d spent most of the night in a dorm lobby attempting to woo a woman I was particularly excited about. I went to the men’s room, and found myself unable to urinate except for a trickle of blood. I spent the rest of the night in the infirmary, where they poured as much water down me as possible without my teeth swimming, cleared my colon, and enabled me to find a comfortable position from which I could pass the clots formed from bleeding–well, we never could determine where the source of the bleeding was, but it definitely went into my bladder that night. I spent the next day in the hospital, undergoing a number of inconclusive tests. Eventually, they let me go with a “seems clear now.” After that, I had intermittent hematospermia. *For the next 29 years.* That brings us to *tonight,* boys. We’ve never been able to determine the source–and some docs just told me not to be too concerned. It’s not abnormalities in the prostate; that much I know. Hell, for a while I did work for the local medical schools as a practice patient and underwent rectal exams–I had to be examined at the beginning of the cycle just to be certain that I wasn’t myself an abnormal patient, and I wasn’t.

After nearly three decades of this–on and off–I’ve concluded that my case is probably in the “vascular irregularity” category. It’s most often linked to a particularly turgid erection, and if I sleep on my stomach, I almost always pass a clot the following morning (since most men get an erection in their sleep, I figure I’m no different, and laying on said erection no doubt places extra pressure on it). If there is going to be blood in my semen, I can frequently tell, because my erection feels subtly different–however, this test is not absolute. Numerous times, I thought I would have an episode, but things were all clear.

My approach to it nowadays is relatively simple. I make sure to stay hydrated if sexual activity seems imminent. In addition to hydration being good for you, I’ve come to learn that if there is blood in my semen, I will inevitably have to pass some blood in my urine, and if it has time to clot, better to have more urine behind it than less. I’ve never again had to pass as copious amounts of blood in my urine as I did during that first episode; not by a long sight. After an episode, I’ll normally try to avoid sex for several days or a couple of weeks, but there’s really no rhyme or reason. Sometimes I could have sex within 24 hours and show no symptoms. Other times, two, three weeks later, with no activity in the meantime, and I’ll still show blood. I do not sleep on my stomach.

By the way, I have never had any of the other symptoms mentioned in this article–back pain, weight loss, what have you. Nor am I engaging in frequent, acrobatic, strenuous, or high-impact sexual activity.


The bloody event occurred three days ago to this 87 year-old man. It was the result of masturbation as my 80 year-old wife suffers from severe depression and is not interested in sex anymore but I am. The ejaculate was a steady very bright red. However I noticed just fifteen minutes later that upon urination my urine was crystal clear and has been ever since. Once before at least three year ago I experienced the same event took place and my urologist told me not to worry that it very well probably was a capillary that momentarily burst whithin the system. So I didn’t worry. I might add that this same urologist has me taking the drug flomax to protect my prostate and it seems to be doing a good job as all recent tests have revealed only a small enlargement in the organ. I have not sought a doctor’s opinion for this latest occurrence and don’t intend to unless the next ejaculation is a repeat. I don’t think it will be.


thank you for this very informative article, also to user eric. lately i’v bin gaining wait and i drink a lot of 3in1 coffee to be specific and yes sometimes i feel dizzy which makes me think i have a high blood pressure problem. i started noticing my hematospermia last 2012 while masturbating. panicked, i rush to see a GP and gave me sum antibiotics, and honestly i did not believe her, i surf the internet instead, luckily i found answers like this article did. after 2weeks of abstinence blood is gone. then this august 2014 after having sex with my gf i see a lot of blood again. worried so i surf the net again and found this. and what eric said might also apply to me. i hve no other symptoms aside from the blood.


been dealing with this on and off, for the past 4 years.
Never once has there been blood during masturbation. Ever!!!
However it is now to the point that regular intercourse will result in bloody semen. Which very very quickly clots up.
I have to be basically full of water prior to intercourse. Then immediately go pee ASAP, after intercourse. If not it will clot up. Very painful to pass several clots. Sometimes taking the whole day. I once had to go to the emergency dept to have a catheter inserted to relieve the pressure followed by passing of clots.
I have not had any injuries or accidents, good PSA results, regular prostate exams, biopsy samples taken of my prostate ( extremely painful ) and no cancerous tissues.
My urologist is not concerned, but this is very taxing.


I for the last three weeks have been passing blood on ejaculation, it started as spotting, then watery blood, its now 90% blood. I have been to the doctors, he gave me finger up the arse treatment, tested blood pressure, urine test for blood which was clear. i’m 55 and type 2 diabetic he sent me to see a specialist at the hospital who gave me the anal finger treatment again where he confidently stated I have an enlarged prostate and he believes a condition called Prostatitis. he has given me a 28 day course of antibiotics which I prey works. just had sex with my wife, not intercourse but she gave me a hand job and the condition is the same, all blood. Very scary, just got to wait and see what happens after tablets finished. going private if it does not work with tablets…. I am very worried as is the wife, looked into prostatitis and its says everywhere its very painful, well, I have had no pain so I have concern over diagnosis, they either don’t no what’s up or they like fingering peoples arse holes, my advice is get as many opinions as you can and don’t sit about listening to so called experts, keep moving forward at all times making as much noise as possible.. after all they are not the ones with the worries and the blood coming out of their dicks,,, do your doctors head in at all times that’s what we pay for in out tax and health stamps after all.


I’m 84. I note here that guys some years older have reasonably successful orgasms. I had a fifteen year period of total sexual abstinence for religious reasons when I was younger, which I now regret. My first masturbation after that produced a gelatinous brown semen which scared the hell out of me. Since then I’ve had BPH and was on Finasteride for about 25 years. About 5 years ago, as males in my family develop prostate cancer, despite frequent visits to my Eurologist I was diagnosed with a Gleason in the low seven range. Mind you I had a GP and a Eurologist tell me after a cystocopy that I was cancer free and the GP said the blood was probably a crystal in my eurethra. Subsquently, after hormonal treatment at Sloane and radiation, I’ve been okay but now my BPH is increasing (or is cancer coming back?) Recently a bone and cat scan showed “enlargement of the prostate” Is BPH common after all that treatment? Last night an attempt at masturbation resulted in no orgasm and no ejaculation. After struggling to hit the spot, I just gave up. Went to Yoga. Astanga. This morning two pink spots show on my sheets and a trial of my first drops of urine on a white napkin showed pink. My next urination was clear. Hoping its simple BPH and not an increase in cancer. Have an appt. with my radiologist in 2 weeks and will talk about all of it. I need to know if if a return of cancer would show up in recent cat and bone scans I had. At Sloane, a nurse reading the results and my GP say “all seems clear” but your prostate, though not as large as it was before treatment, is now getting larger.” The other question is: Is it really only more BPH which i’ve had since thirty y.o. or… is the cancer coming back? If not cancer, is there any remedy besides my one FLOMAX one half hour after dinner. Just one makes me dizzy in Yoga or do I have to bite the bullet and now take two a day or go back to finasteride? I had the green light about nine years ago, before the cancer diagnosis; , but now the old prostate is growing. If just more BPH can the green light be done a second time. Also are there other measures for BPH considering my medical history? Please don’t let the answer be more cancer, more hormonal shots and more radiation. I had forgotten I had those problems and I’m still working long hours a day at what I do. Thanks men.

We’re a group of volunteers and opening a new scheme in our community.
Your website offered us with valuable info to work on. You’ve done an impressive job and our whole community will be grateful to you.


Can you please refer me to the doctor who wrote this article, I would like to make an appointment to see him because my life is really depressing with this situation and my doctor didn’t seem intrested in solving it. Thank you


Thanks for this valuable information.I have had some blood in my semen. I had a PSA, ultrasound and a rectal test..Everything is ok..Since then my life style has changed a lot..I have to be more concern about my health and diet because I’m already 60 and my wife 35 jaja..Now I know I can do things to have a better life and health..I suggest that with the first alarm we have to see a doctor immediately..Thanks a lot Doctor,your opinion is worth a fortune..

Arif Aslam

Dear I am 25 year old unmarried semen dishcahge watery brownish and sharp smelly problem slowly slowly increase this problem since 7 year .i got mastubation penile erection very low all test are mormal lh fsh prl urine fungal culture syphllis etc plz give me advise


I am 50 years old. I have had blood in semen for over 2 years. Sometimes even an erotic dream (without ejaculating) leads to blood in urine. Few brief periods were it stopped for a short time. I also get clots in my urine after ejaculation, and sometimes it is so difficult to poss that I must wait until the following day to develope enough pressure to get the urine out. Often when urine does finally come out, it’s extremely messy because of spray from the pressure buildup. It’s awful. Never mind the uncomfortably of bloody seamen with your partner, blood on sheets…
I have had every test done except for MRI. told by two different urologists, nothing they can do. Hard to believe there is nothing that can help.

Kent Dyer

I am 60. The color of my semen was normal. I had a couple of drops of blood come out with my semen but not mixed in to change the color. Kinda like I had a small cut that dripped into water.


There is a big link between zinc deficiency and hematospermia . Take zinc supplements daily . Every situation is different but in a lot of cases this is the magic pill and you may see a noticeable improvement / absence within a month .

Dr J

No Evidence for zinc whatsoever or selenium or Vitamin E!
The SELECT trial was a randomized controlled study designed to evaluate vitamin E, selenium, and the two in combination in the prevention of prostate cancer. Unfortunately, this study failed to show a benefit from either supplement. Many people were critical of the choice of vitamin E and selenium; these agents were chosen because they had been used in the studies that formed the basis for the SELECT trial.

Now, an update of this study has shown that these agents actually harmed some men. Men with high levels of toenail selenium upon entering the study and who were randomly assigned to receive selenium (either with or without vitamin E) had a 91% increase in high-grade prostate cancer. In addition, men with low selenium levels who received vitamin E alone had a significantly increased risk for total, low-grade, and high-grade prostate cancer.

These findings have two important implications. First, the public needs to recognize that it is false to assume herbs, vitamins, and supplements cannot cause harm. Second, this study again illustrates the importance of properly testing supplements in randomized trials rather than making conclusions from epidemiologic or uncontrolled case studies.
Caveat Emptor

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