Menstrual blood color turning dark is an indication of toxins in the uterus.

Menstruation is an important indicator of women’s health, like a “barometer” of the body’s status. Western medicine explains that menstruation results from the periodic shedding of the endometrium causing bleeding; while traditional Chinese medicine refers to it as “monthly affairs” or “monthly water,” also referring to the phenomenon of uterine bleeding. Under normal circumstances, menstruation should be dark red, with the initial period possibly appearing slightly darker due to poor blood flow. There is a belief in society about menstrual detoxification, and if the color of menstruation deviates from normal, people may worry about toxins accumulating in the uterus.
In fact, when the color of menstruation is dark for two consecutive months, it is often related to the following three aspects:
First is lifestyle habits. Unhealthy habits such as wearing revealing clothing during menstruation, craving cold and spicy foods, intense exercise, sexual activity, smoking and alcohol habits, extreme dieting, or long-term stress can lead to hormonal imbalances, affecting the color of menstruation which may appear dark.
Secondly, infections in the reproductive system. For example, pelvic inflammatory diseases affecting the fallopian tubes, endometrium, often caused by frequent sexual activity or infections, with symptoms such as abdominal pain, increased secretions, darkening of menstruation, increased flow, and extended cycle. Genital tuberculosis affecting the pelvic cavity, ovaries, fallopian tubes, caused by tuberculosis bacteria, can lead to changes in the endometrium early on, presenting as dark and heavy menstruation, and in severe cases can lead to reduced or stopped menstruation.
Furthermore, factors related to reproductive organ tumors. Uterine fibroids, a benign tumor of muscle tissue related to hormone levels, common symptoms include increased menstrual flow and extended cycle, under specific conditions can also cause menstruation to become dark. Ovarian tumors, whether benign or malignant, when enlarged can disrupt the regularity of menstruation, causing changes in menstruation color and other symptoms in late-stage malignant tumors.
In reality, menstruation is a natural physiological process of the endometrium shedding, not a detoxification mechanism, and the body does not need to expel “toxins” through menstruation. Therefore, occasional darkening of menstruation should not cause excessive worry about the rumor of “uterine toxicity.” If feeling uneasy about this, it is advisable to seek timely medical attention and receive appropriate evaluation and treatment from a professional doctor.