Seeing blood in semen (hematospermiaorhemospermia)can cause worry.
Only in rare cases is blood in semen a warning sign of a more serious condition.
For men over 40, chances are higher that they will need medical evaluation and treatment.

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This article covers the common causes and when someone should see a doctor.
Trauma examples causing blood in semen include:
3.
The American Cancer Society (ACS) says prostate cancer is rare in men under 40.
Risk increases with age.
Blood Disorders and Blood Vessel Problems
Blood disorders and blood vessel problems may also be behind blood in semen.
Examples include:
5.
Recent Test or Procedure
Blood in semen can be due to recent tests and medical procedures.
The following tests and procedures can cause blood in semen:
6.
Current Treatment Plan
Current treatment plans for health conditions may cause semen in the blood.
These include treatment plans involving:
7.
Tumors and Polyps
Tumors, polyps, and in rare cases cancers, can also cause blood in semen.
Treatment Options
Treatment depends on the cause.
For blood in semen due to bacterial infections,treatment may include antibiotics.
An electric current is used to stop bleeding in the seminal vesicles, urethra, and prostate.
Underlying health conditions, includinghigh blood pressure, should also be treated.
Summary
While unsettling, blood in semen usually nothing serious.
It typically resolves on its own.
In some cases it may indicate underlying health conditions.
Causes include infection, treatments and procedures, sexual activity, prostate problems, and medication side effects.
American Academy of Family Physicians.Evaluation and treatment of hematospermia.
Mathers MJ, Degener S, Sperling H, Roth S.Hematospermia-a symptom with many possible causes.Dtsch Arztebl Int.
2017;114(11):186-191. doi:10.3238/arztebl.2017.0186
NHS.Blood in semen.
Harvard Health Publishing.Hematospermia demystified.
American Cancer Society.Key statistics for prostate cancer.
British Association of Urology.Blood in the semen (haematospermia).
UCSF Health.FAQ: Radiation therapy for prostate cancer.