You are describing what we refer to as hematospermia — or simply, blood or rust colored discoloration of the semen (which contains the sperm and other prostatic secretions). You probably noticed this during ejaculation.

Hematospermia is distressing, but very common. In most cases, it’s benign. The first time people see blood or a rusty color in the semen, it often causes great concern. It may come back. But it usually goes away without any special treatment.

Hematospermia can be caused by:

• An infection in the prostate gland
• Stress that puts pressure on the prostate gland (such as when riding a bike)
• Excessive masturbation

But most often, we cannot identify a specific cause of the hematospermia.

Patients who have had any urological procedures may experience hematospermia that lasts for as long as 4-5 weeks. This is especially true in the case of a prostate needle biopsy.

If the condition persists, you should visit a urologist. The semen is stored in the portion of the prostate area called the seminal vesical, so your doctor may order a specialized MRI test that looks at this area. Hematospermia that persists is rarely a sign of prostate cancer. Still, you should see your doctor to make sure.