Bacterial vaginosis (BV) produces a thin, grayish or yellow-green discharge that often has a noticeable fishy smell. Unlike yeast infections or other vaginal conditions, BV rarely causes visible redness, swelling, or irritation on the outside of the body. What you’ll notice is almost entirely about the discharge itself.
What BV Discharge Looks Like
The hallmark of BV is a thin, watery discharge with a milklike consistency. It coats the vaginal walls smoothly rather than clumping or forming chunks. The color ranges from off-white to gray to yellow-green, and it can be foamy in some cases. The volume varies, but it’s often more than what you’d consider normal for your body.
The texture is the biggest visual clue. BV discharge is homogeneous, meaning it looks uniform throughout rather than lumpy or curd-like. If you see it on underwear or a liner, it typically appears as a thin, even smear rather than distinct clumps or spots.
The Fishy Smell
BV’s most distinctive feature isn’t visual at all. The discharge carries a fishy odor that can range from faint to strong. It tends to become more noticeable after sex and during menstruation, because both semen and blood are alkaline, which releases the compounds responsible for the smell. Some people notice it throughout the day; others only catch it at specific times.
This odor is so characteristic that clinicians use it as one of four diagnostic markers. During an exam, a sample of discharge is mixed with a chemical solution. If a fishy smell emerges, that’s considered a positive result for BV.
What BV Doesn’t Look Like
BV typically doesn’t cause the kind of external symptoms you might expect from a vaginal infection. There’s usually no redness, swelling, or soreness around the vulva. Itching and irritation are uncommon with BV, though not impossible. Up to 84% of people with BV don’t have symptoms at all, so many cases go entirely unnoticed.
This is one of the easiest ways to tell BV apart from other conditions just by looking. A yeast infection, for example, usually brings visible inflammation: redness, swelling, and itching around the vulva and vaginal opening. Trichomoniasis, a sexually transmitted infection, also tends to cause noticeable irritation and soreness that BV does not.
BV Discharge vs. Yeast Infection Discharge
These two conditions look quite different once you know what to compare.
- BV discharge is thin, grayish or yellow-green, watery or foamy, and has a fishy odor. It spreads evenly.
- Yeast infection discharge is thick, white, and odorless. It’s often described as looking like cottage cheese, with visible clumps or a white coating in and around the vagina.
If what you’re seeing is chunky and white with no smell but significant itching, that points toward a yeast infection. If it’s thin, grayish, and smells fishy with little to no itching, BV is more likely.
What Happens During Diagnosis
Because BV’s visual signs overlap with other conditions, a clinical exam looks at more than just appearance. Diagnosis typically requires at least three of four markers: the thin, milklike discharge; a vaginal pH above 4.5 (healthy pH sits between 3.8 and 4.5); a positive result on the fishy-odor test; and the presence of “clue cells” under a microscope.
Clue cells are what make BV visible at the microscopic level. Normal vaginal cells have smooth, clearly defined edges. In BV, bacteria coat the outside of these cells so densely that the edges look rough, grainy, and stippled, almost like the cell has been rolled in sand. When a clinician sees these under a microscope, it’s a strong confirmation of BV.
Why Appearance Alone Isn’t Enough
Looking at your discharge can give you a reasonable guess, but color and texture alone won’t confirm BV. The pH shift and bacterial overgrowth happening inside the vagina aren’t things you can see with the naked eye. Gray, thin discharge with a fishy smell is a strong signal, but similar-looking discharge can occasionally come from other infections or even normal hormonal fluctuations.
If you’re noticing a change in your discharge that matches what’s described here, especially the combination of thin texture, grayish color, and fishy odor, that pattern is distinctive enough to warrant getting tested. The test itself is quick and straightforward, and treatment is typically a short course of antibiotics that resolves symptoms within a few days.