The internet has revolutionized our access to information, offering insights on almost every topic imaginable. With just a few clicks, questions that would have puzzled people for ages can now be answered instantly.

One question that’s recently gained attention online is why some women notice “bleach” stains on their underwear. For those who have wondered about these mysterious spots, rest assured—you’re not alone. Many women have taken to online forums seeking answers, and experts have provided some surprising explanations.

It turns out, these spots aren’t caused by your laundry detergent or washing machine. According to Dr. Vanessa MacKay of the Royal College of Obstetricians and Gynaecologists, the answer lies in the body’s natural processes. She explains that the vagina has a self-cleaning mechanism, producing natural secretions that maintain a healthy balance of beneficial bacteria.

These secretions are mildly acidic, with a pH level between 3.8 and 5.0, according to the National Institutes of Health. Since the neutral pH level is 7, this natural acidity can sometimes lead to discoloration on underwear, which may appear like a bleach stain.

Dr. MacKay also notes that it’s normal for women to experience clear or white discharge, which plays a role in keeping the vagina healthy. However, if this natural balance is disrupted, it can lead to infections. So, while these spots may be surprising, they’re a sign that your body’s self-cleaning system is working.

If you found this helpful, consider sharing it with friends and family to help answer a common question many women may be too shy to ask.