Bacterial vaginosis (BV) primarily shows up as a thin, milky white or grayish discharge that coats the vaginal walls evenly. Unlike a yeast infection, which produces thick, clumpy discharge, BV discharge has a smooth, almost milk-like consistency and is often heavier in volume than normal. The other hallmark sign is a noticeable fishy odor, which can be stronger after sex.
What the Discharge Looks Like
The most distinctive visual feature of BV is the character of the discharge itself. It tends to be thin and homogeneous, meaning it looks uniform rather than lumpy or textured. The color ranges from off-white to gray, and it spreads smoothly across the vaginal walls rather than clumping in one area. Some women describe it as watery or having the consistency of skim milk.
Volume varies from person to person, but most women with symptomatic BV notice more discharge than usual. It may leave a visible residue on underwear that looks grayish or slightly yellowish once dried. The fishy smell is often the symptom that prompts a search like this one, and it can intensify during menstruation or after unprotected sex because both raise the vaginal pH.
What You Won’t See
BV generally does not cause the kind of visible external changes you might expect from an infection. There’s typically no redness, swelling, or rash on the vulva. Pain is uncommon. Some women experience a mild burning sensation while urinating, and in rare cases, slight itching. But if you’re looking at the external skin and expecting obvious irritation, BV usually won’t show it. This is one of the reasons it can be tricky to identify on your own.
It’s also worth knowing that many women with BV have no visible symptoms at all. The bacterial imbalance can exist without producing noticeable discharge or odor, which is why it sometimes gets picked up incidentally during a routine exam.
How BV Looks Different From a Yeast Infection
These two conditions are easy to confuse, but their discharge looks quite different once you know what to compare.
- BV discharge: thin, smooth, grayish or milky white, fishy odor, typically no significant itching or pain
- Yeast infection discharge: thick, white, cottage cheese-like texture, little to no odor, often accompanied by intense itching, burning, and sometimes pain during sex
The external symptoms matter here too. Yeast infections commonly cause redness and swelling around the vulva. BV rarely does. If you’re experiencing significant itching and thick, clumpy discharge, a yeast infection is the more likely culprit. If the discharge is thin with a strong smell but minimal irritation, BV is more probable.
How Doctors Confirm It
Because BV can look subtle, diagnosis usually involves more than a visual check. Clinicians use a set of four criteria, and meeting at least three confirms the diagnosis:
- Thin, homogeneous discharge that coats the vaginal walls smoothly
- Vaginal pH above 4.5 (a healthy vagina is more acidic, sitting below 4.5)
- Fishy odor when the discharge is exposed to a chemical solution
- Clue cells visible under a microscope
Clue cells are the most specific indicator. These are normal vaginal skin cells that have become coated with bacteria, giving them a rough, speckled appearance under magnification. Instead of having clean, sharp edges, the cells look like they’ve been peppered with tiny dots. You can’t see this with the naked eye, which is why a lab component is part of the standard workup.
What Happens After Treatment
BV is treated with antibiotics, either taken orally or applied as a vaginal gel or cream. Symptoms typically clear within a few days of starting treatment, and the discharge should return to its normal color, consistency, and volume.
The challenge with BV is recurrence. Between 50% and 80% of women who complete a course of antibiotics experience BV again within 6 to 12 months. This high recurrence rate means that noticing the visual signs early, particularly the shift to thinner, grayer discharge with a fishy smell, can help you catch it quickly if it returns. Some women learn to recognize the subtle change in discharge before the odor even becomes noticeable, which can prompt earlier treatment.
What’s Actually Happening Inside
BV isn’t caused by a single invading germ. It’s a shift in the balance of bacteria that naturally live in the vagina. In a healthy vaginal environment, beneficial bacteria keep the pH acidic (below 4.5), which limits the growth of other organisms. When those protective bacteria decline, other species multiply, raising the pH and producing the compounds responsible for the fishy odor and changed discharge.
This is why BV doesn’t look like a typical infection with redness and swelling. There’s no immune response attacking an outside invader. Instead, the existing bacterial community has simply tipped out of balance. The discharge you see is the visible result of that shift: a change in the chemical and microbial environment rather than tissue inflammation.