The blood in the semen may be seminal vesiculitis, prostatitis, seminal vesiculitis stones, etc., and should be consulted to find out the cause of the disease. 1. Spermatitis: Spermatitis refers to inflammation of the seminal vesicle area caused by bacterial or lymphatic infection. The main manifestation is pain, frequent urination, urinary urgency, also can show blood, that is, when ejaculation semen will appear blood, blood clots of the situation. 2. Prostatitis: Prostatitis is an acute and chronic inflammation of the prostate gland caused by an infection. The main symptoms of prostatitis are pain or discomfort in the pelvic area, frequent urination, urinary urgency, painful urination and even blood in the urine, as well as the presence of blood in the semen. 3. Seminal vesicle stones: Seminal vesicle stones are symptoms of stones that occur inside the seminal vesicles. It is usually caused by seminal vesiculitis, various infections and trauma. Its main manifestations are painful ejaculation, painful urination, and also symptoms of bloody semen. The appearance of blood in the semen suggests that the patient should consult a doctor in time, so that the doctor can clarify the cause of the disease and give targeted treatment.