There are various clinical reasons why a woman’s discharge is brown. The most common cases are as follows: 1. It may be because of gynecological inflammation, such as common endometritis, vaginitis, pelvic inflammatory disease, and tubal inflammation. Endometritis and vaginitis are the most common reasons why the discharge is brown. This is because when a woman suffers from endometritis or vaginitis, the permeability of the skin mucosa at the onset site will increase, causing substances in the blood vessels to leak out onto the surface of the skin mucosa. These factors can lead to brownish discharge. 2. For older women, such as those over 40 years old, it is important to suspect tumor diseases, such as endometrioma and vaginal rhabdomyoma, which are often seen. When women have tumor diseases, it can also lead to brown vaginal discharge.