The brown discharge on the panties during ovulation is caused by the fluctuating hormone levels in a woman’s body during ovulation. When the follicles start to develop, they begin to secrete a small amount of estrogen, which reaches a peak in the woman’s body just before ovulation and then decreases slightly after ovulation. In addition, during the follicular phase the follicles generally do not secrete luteinizing hormone, after ovulation they secrete a small amount of luteinizing hormone. Therefore, during ovulation, as the estrogen and progesterone in the body are relatively low, the endometrium loses hormonal protection, there is a small amount of shedding, and a small amount of brown discharge will appear. Such a discharge usually indicates the arrival of ovulation, and the amount is relatively small, and will clean itself in 2-3 days, because the hormone level in the woman’s body starts to rise after 2-3 days.