Bacterial vaginosis (BV) discharge is typically thin, watery, and grayish-white, with a noticeable fishy smell. It’s one of the most common vaginal infections, and its discharge looks and feels distinctly different from normal vaginal moisture or other infections like yeast. If you’ve noticed a change in your discharge and you’re trying to figure out what’s going on, here’s what to look for.
Color, Texture, and Volume
BV discharge is usually thin and watery rather than thick or clumpy. The color ranges from white to gray, and in some cases it can have a greenish tint. It tends to coat the vaginal walls evenly rather than coming out in chunks or curds. Many people notice an increase in volume, sometimes enough to leave a noticeable mark on underwear throughout the day.
The consistency is one of the easiest ways to distinguish BV from a yeast infection. Yeast infections produce thick, white discharge often described as looking like cottage cheese. BV discharge is the opposite: runny, smooth, and more like a film than a paste.
The Fishy Smell and Why It Gets Worse
The hallmark of BV is a fishy odor, and it’s caused by specific chemical compounds (volatile amines) produced when harmful bacteria overgrow in the vagina. In a healthy vaginal environment, beneficial bacteria keep things acidic and balanced. When that balance shifts and the wrong bacteria take over, those bacteria produce waste products that smell distinctly like fish.
The smell isn’t always constant. It tends to spike after sex, because semen is alkaline and temporarily raises vaginal pH, which releases more of those odor-causing compounds into the air. Many people also notice the smell is stronger right after a period, for similar pH-related reasons. If you’re noticing a fishy odor primarily after intercourse or around your cycle, BV is a likely explanation.
Other Symptoms Beyond Discharge
Discharge and odor are the primary signs, but BV can also cause vaginal itching and a burning sensation during urination. These symptoms tend to be milder than what you’d experience with a yeast infection, where itching and irritation are usually front and center. With BV, the discharge and smell are typically what people notice first, and irritation is more of a secondary complaint.
It’s also worth knowing that not everyone with BV has obvious symptoms. Some people have the bacterial imbalance without any noticeable change in discharge or odor, which means it sometimes gets picked up incidentally during a routine exam.
BV Discharge vs. Yeast Infection vs. Normal
Normal vaginal discharge changes throughout your cycle. It can be clear and stretchy around ovulation, white and creamy at other times, and varies in volume. It shouldn’t have a strong or unpleasant odor. If your discharge has always looked a certain way and suddenly changes, that’s worth paying attention to.
- BV: Thin, grayish-white, fishy smell, heavier volume than usual. Smell worsens after sex or periods.
- Yeast infection: Thick, white, cottage cheese texture. Usually no strong odor, but significant itching, redness, and swelling.
- Trichomoniasis: Frothy, yellow-green discharge with a strong odor, often accompanied by irritation and pain during urination.
These descriptions overlap enough that self-diagnosis isn’t always reliable. The distinguishing features of BV, specifically the thin texture combined with the fishy smell, are the most useful clues, but a clinical test is the only way to confirm it.
How BV Is Confirmed
If you go in for testing, your provider will typically take a sample of vaginal discharge and evaluate it in a few ways. One key marker is vaginal pH: a healthy vagina sits below 4.5 on the pH scale, and BV pushes it above that threshold. Under a microscope, BV shows what are called “clue cells,” which are normal vaginal wall cells that have become coated with bacteria, giving them a fuzzy, irregular border instead of a clean edge. The combination of elevated pH, clue cells, the characteristic discharge, and the fishy odor is what clinicians use to make the diagnosis.
Why BV Happens
BV isn’t caused by poor hygiene. It’s the result of a shift in the vaginal microbiome, where beneficial bacteria that normally produce lactic acid and hydrogen peroxide lose ground to other bacterial species. Things that can trigger this shift include douching, new sexual partners, scented soaps or products used internally, and sometimes antibiotics taken for unrelated infections. It’s not classified as a sexually transmitted infection, though sexual activity can influence the bacterial balance.
The infection tends to recur. Even after successful treatment, many people experience BV again within a few months, which is one of the more frustrating aspects of the condition. Avoiding internal fragranced products and douching can help maintain the bacterial balance that keeps BV from coming back.