Seeing red even once after you ejaculate can be alarming, but in most cases, it isn’t actually anything serious.

That reddish tinge is usually due to a common condition called hematospermia, or blood in the semen.
Doctors aren’t really sure what’s responsible for most cases of hematospermia. The condition usually stops quickly by itself.

Still, you want to bring it up to your doctor: He or she will likely test your urine, examine your genitals and urinary organs, perform a digital rectal exam, and check your blood pressure.

This can help your doctor determine a cause for your reddish semen—if there’s one to be found at all.

Men might experience blood in their semen if they have an infection or inflammation in their seminal vesicles, prostate, or urethra.

This is even more likely if you notice burning when you urinate, or pain when you ejaculate. If you experience these symptoms, your doctor will probably evaluate you for a urinary tract infection.

If he or she finds that an infection is to blame, you’ll likely receive a course of antibiotics—and the blood in your semen should go away soon after.

Other possible causes include bleeding disorders, prostate stones, or even high blood pressure. (Doctors aren’t sure why hypertension causes blood in the semen, but it may be because the increased pressure causes the delicate vessels in the prostate and seminal vesicles to burst.)

If the blood in your semen goes away quickly, and your initial evaluation with your doctor didn’t turn up anything abnormal, you don’t need to worry.

But if you keep noticing that reddish tinge for more than 2 months, or after ejaculating more than 10 times, that might point to something more serious.

In that case, your doctor will recommend additional testing, like a transrectal ultrasonography, an MRI of the pelvis, and a cystourethroscopy (also known as a cystoscopy), a visual inspection of the lower urinary tract.

This can help your doctor determine if there are any masses or tumors causing the bleeding.

Rarely, blood in your semen can point to cancer in your genitourinary tract, which includes your bladder, prostate, urethra, penis, and testicles.

In fact, men over 50 who notice blood in their semen should also consider taking a serum PSA test to evaluate their risk of prostate cancer.  (Most urologic cancers are more common in older guys, except testicular cancer, which peaks in the 20s and 30s.)

One important note: While blood in the semen is usually nothing to worry about—especially in younger guys—it can be easily confused with something called gross hematuria, or visible blood in the urine.

Blood in the urine can have a more serious cause, so it’s especially important you go to your doctor so he or she can check out what’s going on.

Source: Mens Health