The normal color of semen is off-white or slightly yellow, and when liquefied it is translucent and milky, those who have not ejaculated for a long time may be slightly yellow. Semen is the fluid discharged from the urethra when a man ejaculates Semen is the fluid discharged from the urethra when a man ejaculates Normal semen is a viscous liquid mixture composed of sperm and seminal plasma. Seminal plasma makes up more than 90% of the volume of sperm. Sperm are produced by the testes, mature in the epididymis and pass through the vas deferens. Usually the normal color of semen is off-white or slightly yellow, those who have not ejaculated for a long period of time may have a light yellow color; if the semen is yellowish-green or reddish, it may be due to inflammation of the male reproductive tract or other gonads, such as prostatitis, prostate tumors, seminal vesiculitis, urethritis, and so on. If the symptom of abnormal semen color persists without relief, it is recommended that patients go to regular hospitals for medical examination and treatment.