A reader sends a letter: I found that my semen is yellowish, I do not know whether it is normal or not, what color is considered normal? In fact, there are quite a few people who have such doubts, and there are many patients who ask such questions in the clinic. First of all, let’s understand the composition of semen, semen consists of spermatozoa and seminal plasma. Sperm volume only accounts for a very small part, more than 90% of the seminal plasma. Seminal plasma is secreted by the prostate, seminal vesicles, urethral bulbourethral glands, urethral pars plana glands and other accessory sex glands, the main component is water, and fat, protein particles, pigment particles, lecithin vesicles, enzymes, fructose and many other components. Secondly, the color of semen is determined by the components that make up semen. Normal human semen is grayish white or slightly earthy yellow, if the abstinence time is longer, due to the physical and chemical properties of the change, the color will be yellow, this is normal. So when you see the semen color is a little yellow, to rule out the problem of whether the abstinence time is too long, if there is still a problem and then do further examination to clarify the cause of timely treatment. Here are some more information for the readers about the abnormal semen, if the following semen color should be timely consultation. 1, the semen is milky white or slightly yellowish green if put under the microscope will see a large number of pus balls, which indicates that there is inflammation in the reproductive tract, is likely to be the prostate and seminal vesicles of the purulent infection. 2, the semen is red, indicating that the semen contains red blood cells, usually called hematospermia. This will often make the patient very worried, thinking that it is a very serious terminal disease. In fact, this is just caused by some inflammation. Hematospermia is mostly caused by seminal vesiculitis or prostatitis. This kind of blood semen caused by inflammation is mostly light red. If small blood vessels rupture due to vascular malformations, the blood semen is bright red and there are blood clots. Serious tumors of the seminal vesicles and prostate can also cause hematospermia, but usually, cancer hematospermia is characterized by persistence and aggravation, unlike hematospermia caused by inflammation. In addition, such as tuberculosis, schistosomiasis or systemic hematologic disorders can occasionally cause hematospermia, and these cases should be treated accordingly. According to clinical observation, when there is bleeding in the reproductive tract, the semen is red or light red, and a large number of red blood cells can be seen under the microscope, and some of them look brownish-red or soy sauce-colored to the naked eye, which is due to a large number of red blood cells in the semen. For these pathologic hematospermia should be timely to find the cause of diagnosis and treatment. The abnormal semen color is not scary, once you find the cause of the symptomatic treatment, the color can be returned to normal.