Bacterial vaginosis (BV) discharge is typically thin, grayish-white or yellow-green, and has a milk-like consistency that smoothly coats the vaginal walls. It often comes with a noticeable fishy smell. Unlike the thick, clumpy discharge of a yeast infection, BV discharge tends to be watery and uniform in texture.
Color, Texture, and Consistency
BV discharge ranges from off-white to gray to yellow-green. The color can vary from person to person and even shift slightly throughout your cycle, but a grayish or dull tone is the most common. The texture is consistently thin and smooth, almost like skim milk. It coats the vaginal walls evenly rather than clumping or forming chunks.
The amount of discharge varies. Some people notice a significant increase compared to their normal baseline, while others see only a modest change. What typically draws attention is the combination of an unfamiliar color, the thin consistency, and the smell rather than volume alone.
The Fishy Odor
The smell is often the most recognizable symptom. BV produces a distinctly fishy odor caused by specific chemical compounds (called amines) that the overgrown bacteria release. This odor tends to become stronger after sex, because semen is alkaline and triggers more of these amines to become airborne. Some people also notice the smell is worse during their period for similar reasons, since menstrual blood raises vaginal pH.
Not everyone with BV gets a strong odor, though. More than half of all people with BV have no noticeable symptoms at all, meaning the discharge change and smell can range from obvious to completely absent.
How BV Discharge Differs From Other Infections
Three common vaginal infections each produce discharge that looks quite different, and telling them apart is one of the fastest ways to narrow down what’s going on.
- BV: Thin, off-white or gray, milky, fishy smell. No itching or irritation in most cases.
- Yeast infection: Thick, white, cottage cheese-like texture. Typically causes itching and burning but little to no odor.
- Trichomoniasis: Profuse, yellow-green, frothy (bubbly) discharge with a strong odor. Often accompanied by irritation, redness, and discomfort during urination.
The frothy quality of trichomoniasis discharge and the chunky texture of a yeast infection are the easiest visual distinctions from BV’s smooth, thin consistency. If your discharge looks gray and watery with a fishy smell but no significant itching, BV is the most likely cause.
What’s Happening Inside
A healthy vagina maintains a slightly acidic environment, with a pH between 3.8 and 4.5. Beneficial bacteria (primarily lactobacilli) keep this pH low, which limits the growth of other organisms. In BV, those protective bacteria are outnumbered by a mix of other bacterial species. This shifts the pH above 4.5, sometimes significantly higher, and the change in bacterial balance is what produces the characteristic discharge and odor.
BV is not a sexually transmitted infection, though sexual activity can increase the risk. It’s fundamentally an imbalance in the vaginal microbiome rather than an invasion by a single pathogen.
How BV Is Diagnosed
Doctors typically diagnose BV using a set of clinical criteria that require at least three of four findings: the thin, homogeneous discharge; a vaginal pH above 4.5; the presence of “clue cells” (vaginal cells coated in bacteria, visible under a microscope); and a fishy odor when a chemical solution is applied to a discharge sample. This last step is called the whiff test.
You can’t reliably diagnose BV at home based on discharge alone, since the visual overlap between infections can be subtle. A provider visit or an at-home vaginal pH test can help point in the right direction, but lab confirmation is the most reliable path.
Treatment and What to Expect
BV is treated with prescription antibiotics, either taken as pills for about a week or applied as a vaginal gel or cream for five to seven days. Most people see the discharge and odor begin to clear within a few days of starting treatment.
One frustrating aspect of BV is its recurrence rate. Many people experience repeat episodes within a few months of treatment. Maintaining the vagina’s natural pH by avoiding douching, scented products, and unnecessary internal washing can help reduce the chances of it coming back, though recurrence sometimes happens regardless of prevention efforts.