Most cases of mucus in semen are totally normal, as there is naturally a certain amount of mucus present in healthy seminal fluids. Men should not normally be concerned if a small amount of mucus is detected upon ejaculation. The main issues with mucus in semen are when the substance is yellow, green, or bloody in color. This could indicate an underlying infection or illness.
Semen is a sticky substance that is comprised of various proteins, sugars, and other biological materials. It is released from the male penis during ejaculation, and it also contains millions of spermatozoa. The semen acts to nurture and nourish sperm cells as they make their way through the female reproductive tract toward the fallopian tubes for the purpose of egg fertilization. In many cases, mucus in semen will be detected. This is normal and acts to help protect and mobilize sperm cells.
Cases where mucus in semen would be a problem involve semen that is an unusual color. While pale yellow semen can sometimes be considered normal, any other variation outside of a normal white shade should be cause for alarm. This is especially true if additional symptoms are present, since this could be an indicator of disease. Sexually transmitted infections are frequent causes for unusually colored semen. Burning, itching, oozing, and blisters are also common with many sexually transmitted diseases.
Yellow semen can be considered normal, or it may mean that urine has leaked into the semen prior or during ejaculation. If there are no other symptoms present and the yellow color is pale, there may be no problem. Yellow mucus in semen could also be pus, which is a sign of serious infection. Males with yellow semen should seek medical care immediately.
Dark green or blood-tinged semen are also signs of infection. The tip of the urethra can become irritated and inflamed with many sexually transmitted diseases, and bleeding may occur during urination or ejaculation. If these or any other symptoms become noticeable, men should be tested for common sexually transmitted infections. Less common health conditions may also cause similar symptoms, although they will typically be accompanied by other symptoms.
Aside from color, there are other ways to determine semen health. Seminal fluids should not have a strong odor, nor should they be watery in nature. Normal semen is thick when it is released and then becomes more watery over time. It is also usually white in color, although more transparent can also be normal. Any variation from a man's usual semen may be cause for concern, even if no other symptoms are present at the time.