Blood in Semen: Causes and When to Get Checked

Blood in semen, medically known as haematospermia or hematospermia, can be alarming. Semen may appear pink, red, reddish-brown or rust-coloured, or contain small streaks or spots of blood.

In most cases, particularly after a single episode in someone under 40 without other symptoms, the cause is not serious. Mild inflammation, infection, recent vigorous sexual activity or a urological procedure can cause a small blood vessel somewhere in the reproductive tract to bleed.

However, blood in semen should still be discussed with a GP, especially when it keeps returning, continues for several weeks, occurs after the age of 40 to 45 or is accompanied by blood in the urine, a testicular lump, fever, weight loss or significant pain.

Blood in semen is rarely caused by cancer, but persistent or recurrent bleeding needs appropriate assessment rather than repeated reassurance without examination.

What does blood in semen look like?

The appearance depends partly on how recently the bleeding occurred.

• Pink or bright-red semen usually suggests relatively fresh blood.
• Dark red, brown or rust-coloured semen often represents older blood that has taken longer to leave the reproductive tract.
• Streaks or small spots may occur when only a small amount of blood is present.
• Repeated discolouration may continue for several ejaculations while old blood clears.

The entire ejaculate may be discoloured, or blood may only appear in part of it. It may happen once and never return, appear intermittently or be noticed every time someone ejaculates for a period.

Blood in semen is different from blood coming from the penis independently of ejaculation. It is also important to establish whether the blood could have come from a partner during sexual activity.

Where can the blood come from?

Semen contains sperm from the testicles together with fluid produced by structures including the prostate gland and seminal vesicles. It travels through the epididymis, vas deferens, ejaculatory ducts and urethra before leaving the penis.

Inflammation, irritation or a small damaged blood vessel anywhere along this pathway can introduce blood into the semen.

Common possible sources include:

• the prostate gland;
• the seminal vesicles;
• the urethra;
• the ejaculatory ducts;
• the epididymis or testicle;
• tissue recently affected by surgery, biopsy or another procedure.

It is often impossible to identify one exact vessel or structure responsible. If the bleeding settles and the assessment is reassuring, finding the precise source may not be necessary.

What are the common causes of blood in semen?

Inflammation or infection

Low-grade inflammation in the prostate or elsewhere in the seminal tract is among the most common explanations. This may occur with or without a confirmed bacterial infection.

Possible conditions include:

• prostatitis, involving inflammation or infection of the prostate;
• urethritis, affecting the tube through which urine and semen leave the body;
• epididymitis or epididymo-orchitis;
• a urinary tract infection;
• inflammation of the seminal vesicles.

Associated symptoms may include pain when urinating, needing to urinate more often, pelvic discomfort, pain during ejaculation, fever, discharge from the penis or pain and swelling in a testicle.

Sexually transmitted infections

Sexually transmitted infections such as chlamydia and gonorrhoea can cause urethral or reproductive-tract inflammation. An STI is not the cause of most cases of blood in semen, but testing may be appropriate after unprotected sex, with a new partner or when there is discharge or painful urination.

Sexual-health clinics offer confidential testing and treatment without requiring a GP referral. Our guide to how sexual-health clinics work in the UK explains what to expect.

Recent sexual activity or minor trauma

Very vigorous or prolonged sex or masturbation may occasionally break a small blood vessel. A direct blow to the groin or perineum can also cause bleeding.

Some people notice haematospermia after a long period without ejaculating. In these situations, it often clears without treatment.

Recent urological procedures

Blood in semen is common after procedures involving the prostate, bladder, urethra or reproductive tract. Examples include:

• a prostate biopsy;
• cystoscopy;
• vasectomy or vasectomy reversal;
• prostate surgery;
• radiotherapy or brachytherapy;
• catheterisation or another urethral procedure.

After a prostate biopsy, semen can remain brown or blood-stained for several weeks or numerous ejaculations. The healthcare team should explain what is expected and which symptoms require further advice.

Prostate enlargement, cysts or stones

Benign prostate enlargement, small cysts, blocked ejaculatory ducts or stones within the prostate, seminal vesicles or ejaculatory ducts can occasionally cause recurrent bleeding. These causes are less common and may require imaging if symptoms persist.

Medicines and bleeding conditions

Blood-thinning medicines and antiplatelet treatments can make minor bleeding more visible or allow it to continue longer. Examples include warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, aspirin and clopidogrel.

Do not stop a prescribed blood thinner because you have seen blood in your semen. Contact the clinician responsible for your treatment, as suddenly stopping it could increase the risk of a blood clot, stroke or another serious problem.

Less commonly, haematospermia can be associated with a clotting disorder, low platelet count, liver disease or a blood disorder.

High blood pressure

Severely raised or poorly controlled blood pressure is an uncommon possible contributor. A GP may therefore check blood pressure as part of the initial assessment.

No identifiable cause

Frequently, no definite cause is found. This is called idiopathic haematospermia. An unexplained episode can still be harmless, particularly when it resolves, examination and tests are normal and there are no concerning accompanying symptoms.

Could blood in semen be cancer?

Cancer is a rare cause of haematospermia. Most people who experience it do not have prostate, testicular or urinary cancer.

Nevertheless, the possibility deserves more consideration when:

• the person is over 40 or 45;
• bleeding repeatedly returns or does not settle;
• there is visible or microscopic blood in the urine;
• the prostate feels abnormal during an examination;
• a PSA blood-test result is abnormal;
• there is a new testicular lump or swelling;
• there is unexplained weight loss, loss of appetite or bone pain;
• there is a strong family history of prostate cancer;
• the person has Black African or Black Caribbean family background, which is associated with higher prostate-cancer risk.

Possible cancers include prostate cancer and, much less commonly, cancer involving the testicle, bladder, urethra or seminal tract. Blood in semen alone is not a reliable sign of any particular cancer.

The British Association of Urological Surgeons advises that an abnormal prostate examination, abnormal PSA result or associated blood in the urine would normally justify further urological investigation. Read its patient guidance on blood in semen.

When should you make a GP appointment?

Contact your GP if you notice blood in your semen. Although a single painless episode is unlikely to represent a serious problem, a clinician can consider your age, medicines, sexual history and other symptoms.

An appointment is particularly important if:

• the blood appears during several ejaculations;
• it keeps returning;
• it has continued for three to four weeks;
• you are over 40 to 45;
• you have blood in your urine;
• urination or ejaculation is painful;
• you have pelvic, groin, lower-back or testicular pain;
• you have a lump, swelling or change in a testicle;
• you have urinary difficulty or a weak urine flow;
• you have penile discharge or may have been exposed to an STI;
• you take anticoagulant or antiplatelet medication;
• you have a bleeding disorder;
• you have recently had a urological procedure but the bleeding is heavier or lasting longer than expected.

Do not avoid the appointment because the symptom feels embarrassing. GPs and urology clinicians regularly discuss urinary and sexual symptoms.

When might blood in semen require urgent help?

Blood in semen by itself is rarely an emergency. Seek urgent medical advice through an urgent GP appointment or NHS 111 if it occurs with:

• fever, chills or feeling significantly unwell;
• increasing pain or swelling in a testicle;
• difficulty passing urine;
• significant pelvic or lower-abdominal pain;
• persistent bleeding from the penis;
• heavy visible blood in the urine;
• symptoms that began after a significant injury;
• unexpected bleeding elsewhere, extensive bruising or a rash of tiny red or purple spots.

Go to A&E urgently if you develop sudden severe testicular pain, especially with nausea or a testicle sitting higher than usual. Testicular torsion can cut off the blood supply and needs emergency treatment.

Call 999 for collapse, severe uncontrolled bleeding or another life-threatening emergency.

What will a GP ask and examine?

The GP will usually begin by confirming that the blood appears in the semen rather than in the urine or coming from a partner.

They may ask:

• when it began and how many times it has happened;
• whether the semen is bright red, pink or brown;
• whether there is pain during ejaculation or urination;
• about urinary frequency, urgency or difficulty;
• about pelvic, back, groin or testicular pain;
• about recent sex, masturbation, abstinence or injury;
• about recent procedures involving the urinary or reproductive tract;
• whether you have fever, discharge or possible STI exposure;
• which medicines and supplements you take;
• about bleeding disorders and prostate-cancer risk factors.

An examination may include:

• measuring your temperature and blood pressure;
• examining the penis and urethral opening;
• feeling the testicles, epididymides and surrounding structures;
• checking for swollen lymph nodes;
• a digital rectal examination to assess the prostate.

During a rectal examination, the clinician inserts a lubricated, gloved finger gently into the rectum. It is brief and allows them to assess the prostate for enlargement, tenderness, firmness or an unusual lump.

What tests might be needed?

The tests depend on age, symptoms, examination findings and whether the bleeding is isolated or recurrent.

Urine and STI testing

A urine sample may be checked for blood and signs of infection. It may be sent to a laboratory for culture. If an STI is possible, testing may include a first-catch urine sample or swab for chlamydia and gonorrhoea.

Blood tests

Possible blood tests include:

• a full blood count;
• kidney and liver-function tests;
• clotting tests;
• tests selected according to symptoms and medical history;
• a prostate-specific antigen, or PSA, test.

A PSA test may be considered for people over 40 to 50, those with an abnormal prostate examination or those with increased prostate-cancer risk. PSA can also rise because of benign prostate enlargement, inflammation, infection, ejaculation and other non-cancerous factors, so the result must be interpreted in context.

Scans and specialist tests

Many people do not need imaging after one uncomplicated episode. If bleeding persists, recurs or accompanies concerning findings, a urologist may arrange:

• an ultrasound of the testicles;
• an ultrasound of the kidneys and bladder;
• a transrectal ultrasound of the prostate and seminal vesicles;
• an MRI scan;
• cystoscopy to examine the urethra and bladder, particularly when blood is also present in the urine.

Not every person needs every test. Extensive investigation after one painless episode in a younger person can produce little useful information, while recurrent symptoms or red flags justify a more detailed assessment.

How is blood in semen treated?

Treatment depends on the likely cause. Often, no specific treatment is required and the blood clears naturally.

Management may include:

• reassurance and monitoring after an isolated uncomplicated episode;
• antibiotics for a confirmed or strongly suspected bacterial infection;
• appropriate treatment for an STI;
• anti-inflammatory treatment when clinically suitable;
• reviewing anticoagulant treatment without stopping it independently;
• managing severely raised blood pressure;
• treating an identified prostate, urinary or testicular condition;
• specialist treatment for a cyst, stone or blocked ejaculatory duct in selected cases.

Antibiotics are not automatically necessary. They do not treat bleeding caused by irritation, a recent procedure or a non-bacterial inflammatory condition, and unnecessary use can cause side effects and contribute to antimicrobial resistance.

If the bleeding followed vigorous sexual activity, temporarily allowing the area to settle may be reasonable. There is usually no medical requirement to avoid ejaculation for a prolonged period, although it makes sense to stop if ejaculation causes significant pain or fresh bleeding.

Does blood in semen affect fertility or sexual partners?

An isolated episode of haematospermia does not usually affect fertility. Blood itself does not normally damage sperm or mean that someone cannot conceive.

However, an underlying condition such as infection, inflammation, obstruction or a testicular problem could occasionally affect fertility. Speak to a GP if blood in semen is persistent and you are having difficulty conceiving.

Haematospermia itself is not contagious. If it results from an STI, the infection can be passed to a sexual partner. Until testing is complete, using condoms or temporarily avoiding sexual contact may be advisable when STI exposure is possible.

Blood can also be distressing for a partner. Explaining that most cases are benign may help, but medical assessment is appropriate if it continues.

Frequently asked questions

Is one episode of blood in semen serious?

One painless episode in a younger person without urinary symptoms, a testicular lump or another warning sign is usually not serious. Contact your GP for advice and monitor whether it happens again.

Why is my semen brown?

Brown or rust-coloured semen commonly contains older blood. It may occur for several ejaculations as blood from a minor bleed or recent procedure gradually clears.

Can frequent ejaculation cause blood in semen?

Vigorous or prolonged sexual activity may occasionally irritate tissue or break a small blood vessel. Recurrent bleeding should not automatically be attributed to frequent ejaculation without medical assessment.

Can not ejaculating for a long time cause it?

Haematospermia is sometimes reported after prolonged abstinence, although other causes may still need consideration. It will often settle, but persistent or recurrent bleeding should be checked.

Can prostatitis cause blood in semen?

Yes. Prostate inflammation or infection is a common possible cause. Other symptoms can include pelvic pain, painful ejaculation, urinary discomfort, frequency or fever, although some people have few additional symptoms.

Does blood in semen mean I have an STI?

Usually not. However, chlamydia, gonorrhoea and other infections can cause reproductive-tract inflammation. Testing is sensible if you have had unprotected sex, a new partner, penile discharge or painful urination.

Can piles cause blood in semen?

No. Haemorrhoids can cause blood from the rectum, but they do not put blood into semen. It may sometimes be unclear where blood noticed after sex or using the toilet originated.

Can an enlarged prostate cause blood in semen?

Benign prostate enlargement may occasionally be associated with haematospermia, particularly in older adults. Because prostate and urinary conditions become more common with age, recurrent bleeding deserves assessment.

Should I stop blood-thinning medicine?

No. Do not stop anticoagulant or antiplatelet medicine without medical advice. Contact your GP or anticoagulation service so they can assess the bleeding and decide whether any tests or medication changes are needed.

How long should blood in semen last after a prostate biopsy?

Discoloured or blood-stained semen can continue for several weeks or many ejaculations after a biopsy. Follow the information provided by your hospital and contact the team if bleeding is heavy, worsening, accompanied by fever or continues beyond the period they advised.

Why does the blood keep returning?

Recurrent haematospermia can result from continuing inflammation, infection, fragile blood vessels, prostate problems, a cyst, a small stone or medicines that affect clotting. Sometimes no cause is found, but repeated episodes should be discussed with a GP.

Can blood in semen be caused by prostate cancer?

It can be, but this is uncommon. Concern is greater when bleeding is persistent or recurrent, particularly after age 40 to 45, or when there is an abnormal prostate examination, raised PSA, blood in the urine or other concerning symptoms.

Should I take a photograph for my GP?

If you feel comfortable doing so, a photograph can help demonstrate the colour and amount when the symptom is intermittent. Store it securely and show it directly during the consultation rather than sending intimate material unless the practice provides an approved method.

Can blood in semen go away without treatment?

Yes. Many cases resolve spontaneously, especially after one isolated episode or a recent urological procedure. Improvement does not remove the need for assessment when bleeding keeps returning or warning signs are present.