The internet is one of the greatest inventions of modern times, thanks to its endless supply of shared knowledge. As the article puts it, “With a few mouse clicks and keystrokes on a computer, mysteries that would have stayed unsolved for decades can suddenly be resolved.”

One such mystery is the appearance of bleach-like stains on women’s underwear. Many have wondered about this, and it turns out, it’s perfectly normal. These lighter patches are caused by the vagina’s natural acidity.

A tweet clarified: “It’s completely normal to discover lighter patches in a woman’s underwear… due to the acidic nature of the vagina, with a pH range of 3.8–4.5.”
Dr. Vanessa MacKay of the Royal College of Obstetricians and Gynecologists explains, “The vagina has a natural secretory system that allows it to clean itself,” protected by good bacteria.

The National Institutes of Health confirms the vagina’s pH usually ranges from 3.8 to 5.0, making it acidic compared to the neutral pH of 7. As Dr. MacKay notes, “It’s perfectly normal and healthy for women to have clear or white discharge.”So, no need for concern—those marks are actually a sign of good vaginal health.