The quickest way to tell a yeast infection from bacterial vaginosis (BV) is by the discharge. Yeast infections produce thick, white, odorless discharge that looks like cottage cheese, while BV produces thinner, grayish, foamy discharge with a noticeable fishy smell. But symptoms can overlap, and getting it wrong means using the wrong treatment, so the differences are worth understanding in detail.
Discharge: The Most Reliable Clue
Discharge is the single most distinctive difference between these two conditions, and it’s the first thing to pay attention to.
With a yeast infection, discharge is thick, white, and clumpy. It’s often compared to cottage cheese. You might also notice a white coating on the walls of your vagina or on the vulva. The discharge typically has no strong odor at all.
BV discharge looks and behaves differently. It tends to be grayish or off-white, thinner than yeast discharge, and sometimes foamy. The defining feature is the smell: a fishy odor that can be especially strong after sex. That fishy smell is so characteristic of BV that clinicians actually use it as part of the diagnostic process.
Itching, Burning, and Pain
Both infections can cause itching and burning when you urinate, which is part of why they’re so easy to confuse. But the intensity and location of discomfort differ.
Yeast infections are strongly associated with external irritation: itching, redness, and swelling around the vulva. Sex can be painful, and you may feel a burning sensation during urination. The discomfort tends to be constant and hard to ignore.
BV can also cause itching and burning, but many people with BV have mild symptoms or notice only the discharge and odor. Some have no symptoms at all. If intense vulvar itching and redness are your primary complaints, a yeast infection is the more likely culprit. If the smell is what got your attention, BV is more probable.
What Causes Each One
Despite feeling similar at times, these are fundamentally different types of infections. A yeast infection is caused by an overgrowth of fungus (usually Candida) that naturally lives in the vagina in small amounts. BV happens when the balance of bacteria in the vagina shifts, with normally protective bacteria declining and other bacteria multiplying.
The triggers are different too. Yeast infections commonly follow a course of antibiotics, which can wipe out the bacteria that normally keep yeast in check. Hormonal changes, high blood sugar, and a weakened immune system also increase your risk. BV is more closely linked to changes in the vaginal bacterial environment, and things like douching, new sexual partners, or using scented products in the vaginal area can set it off.
Why Getting the Right Diagnosis Matters
These two infections require completely different medications. Yeast infections are treated with antifungal medications, some of which are available over the counter at any pharmacy. BV requires prescription antibiotics. An antifungal will do nothing for BV, and an antibiotic won’t clear a yeast infection.
This is where self-diagnosis gets risky. Studies show that when doctors evaluate vaginal symptoms, BV turns out to be the cause 40 to 50 percent of the time, while yeast infections account for only 20 to 25 percent of cases. Most people assume they have a yeast infection and reach for an OTC treatment, but BV is actually more common. Another 15 to 20 percent of cases turn out to be trichomoniasis, a sexually transmitted infection with its own set of treatments.
Untreated BV carries real health risks beyond discomfort. It increases your susceptibility to HIV and other sexually transmitted infections like chlamydia and gonorrhea. Those infections can lead to pelvic inflammatory disease, which can affect fertility. If you’re pregnant, untreated BV raises the risk of preterm delivery. BV sometimes resolves on its own, but treatment significantly reduces these risks.
What At-Home pH Tests Can and Can’t Tell You
You can buy vaginal pH test strips at most pharmacies. They work by holding a small piece of pH paper against the vaginal wall for a few seconds, then matching the color to a chart. A normal vaginal pH during reproductive years falls between 4.0 and 4.5. BV typically raises vaginal pH above that range, while yeast infections usually don’t.
The FDA notes that these home tests show good agreement with clinical results, but with an important limitation: an elevated pH tells you something has changed, but it can’t tell you what. BV, trichomoniasis, and other conditions all raise pH. And a normal pH reading doesn’t rule out infection either. A negative result could actually point toward a yeast infection, since yeast doesn’t shift pH the way bacteria do. Think of pH strips as one data point, not a diagnosis.
A Quick Side-by-Side
- Discharge appearance: Yeast infections produce thick, white, cottage cheese-like discharge. BV produces thin, grayish, sometimes foamy discharge.
- Odor: Yeast infections have little to no smell. BV has a distinctive fishy odor.
- Primary discomfort: Yeast infections cause intense itching, redness, and swelling. BV may cause mild itching but is often defined more by discharge and smell.
- Vaginal pH: Typically normal (4.0 to 4.5) with a yeast infection. Usually elevated above 4.5 with BV.
- Treatment type: Yeast infections respond to antifungal medication (some OTC). BV requires prescription antibiotics.
When Self-Treatment Makes Sense
If you’ve had yeast infections before, recognize the thick white discharge and vulvar itching, and have no unusual odor, treating with an OTC antifungal is reasonable. But if your symptoms don’t match that pattern clearly, or if an OTC treatment doesn’t resolve things within a few days, it’s worth getting tested. A simple office visit or telehealth appointment can usually sort it out quickly with a swab or pH test.
If you notice a fishy smell, grayish discharge, or symptoms that keep coming back despite treatment, those are strong signals that something other than a straightforward yeast infection is going on. BV recurrence is common, and repeated episodes may need a different treatment approach than a single course of antibiotics.