Trichomoniasis vs BV:
What’s the Difference?

Written by Kathleen Morrison
Medically Reviewed by Andrea Sleeth WHNP-BC, MSCP

Key takeaways

• BV is caused by a bacterial imbalance, while trichomoniasis (trich) is a sexually transmitted parasite—one isn’t the other, but you can have both.
• Symptoms can overlap, but BV usually brings thin, grayish discharge and a fishy odor, while trich often shows frothy yellow-green discharge and burning or itching.
• Proper testing—either in-clinic or at home—is the only way to know what’s going on, especially since both can be asymptomatic at first.
• Treatment works best when tailored: BV with targeted antibiotics like metronidazole, trich with metronidazole or tinidazole, and don’t forget to treat partners, too.
• Prevention and follow-up matter—maintaining vaginal health, regular STI screening, and finishing your full treatment course help reduce reinfections and keep your sexual health in check.

BV and trichomoniasis can feel pretty similar, which is why so many people get confused. Both are common vaginal infections, but they happen for very different reasons.

BV comes from an overgrowth of bacteria in your vagina, while trichomoniasis is a sexually transmitted infection caused by a tiny parasite called Trichomonas vaginalis. Knowing the difference makes getting the right treatment way simpler.

One doesn’t turn into the other, but you can absolutely have both at the same time—more common than you might think. The main difference shows up in symptoms: BV usually comes with thin, grayish discharge and a fishy smell, while trichomoniasis often brings frothy yellow-green discharge, plus itching, irritation, or general discomfort (ick).

Because these infections can feel similar, the only way to know for sure is through reliable testing.

A quick breakdown of BV vs. Trichomoniasis

Here’s a quick, no-nonsense breakdown of what to look out for, how they’re different, and what treatment usually looks like:

Early signs:

• BV: You might notice a thin, watery discharge or a mild fishy smell.
• Trichomoniasis: It can start with genital itching or a small change in discharge.

Main symptoms:

• BV: Gray/white discharge, a stronger fishy odor after sex, and some vaginal irritation.
• Trichomoniasis: Frothy yellow-green discharge, a foul or fishy smell, and burning when you pee.

Cause:

• BV: An imbalance in your natural vaginal bacteria.
• Trichomoniasis: A parasite called Trichomonas vaginalis—yes, it’s an STI.

Transmission:

• BV: Not technically an STI, though sexual activity can sometimes trigger it.
• Trichomoniasis: Sexually transmitted—anyone who’s sexually active can get it.

Treatment:

• BV: Usually antibiotics like metronidazole or clindamycin.
• Trichomoniasis: Prescription antibiotics like metronidazole or tinidazole.

Who can get it:

• BV: Only people with vaginas will experience symptoms, but males can carry it (and pass it around).
• Trichomoniasis: All genders can be infected.

Diagnosis:

• BV: pH test, whiff test, and looking at cells under a microscope.
• Trichomoniasis: Microscopy for parasites or NAAT testing.
  

What is Bacterial Vaginosis?

Bacterial vaginosis (BV) happens when the balance of bacteria in your vagina gets thrown off. Think of your vaginal microbiome like a garden where good and not-so-good bacteria usually coexist peacefully. When that balance tips, the “bad” anaerobic bacteria multiply too fast, crowding out the helpful lactobacilli that normally keep things in check.

BV is actually the most common vaginal condition for people with vaginas, but what makes it tricky is that loads of those affected don’t notice any symptoms at all.

If you do notice something, it’s usually that distinct fishy smell that gets stronger after sex or during your period. The discharge tends to be thin and grayish-white, almost like watered-down milk.

Common symptoms of BV

BV symptoms can range from barely noticeable to pretty uncomfortable. Here’s what to look out for:

• Thinner-than-usual vaginal discharge that’s gray or white
• A fishy odor, often more noticeable after sex or during menstruation
• Mild itching or burning, especially when peeing
• A general feeling that something just isn’t right down there

The odor is caused by amines released when your pH balance shifts. Semen can temporarily raise vaginal pH, which is why the smell can get stronger after sex.

Risk factors for BV

Some things can make BV more likely. These include:

• Having multiple sex partners or a new partner
• Douching, which washes away protective bacteria
• Using scented soaps, bubble baths, or vaginal deodorants
• Smoking cigarettes
• Using IUDs for birth control
• Natural hormonal changes during pregnancy or menstruation

And just to clear the air—myths like getting BV from toilet seats, swimming pools, or sharing towels? Totally not true.

What is Trichomoniasis?

Trichomoniasis—often just called “trich”—is a sexually transmitted infection (STI) caused by a tiny parasite you can’t see without a microscope.

This single-celled troublemaker, Trichomonas vaginalis, loves warm, moist places, making the genital area its ideal home. Unlike BV, trich is always passed through sexual contact, so it’s a true STI.

Like BV, it often doesn't show up with super noticeable symptoms, so it can spread without anyone realizing it. Trich can affect anyone who’s sexually active, though people with vaginas tend to notice symptoms more often than those with penises.

When symptoms do show up, they usually appear within a few days or weeks of exposure, but some people might not notice anything for months.

Convenient at-home STI tests can detect trich along with other infections, and clinicians review results and provide treatment if needed.

Common symptoms of Trich

When trich shows up, the symptoms can be pretty noticeable:

• Frothy or foamy discharge that can be yellow, green, or gray
• Strong, unpleasant, fishy odor
• Intense itching and irritation in and around the vagina
• Burning while peeing and discomfort during sex
• Red, swollen vulva, and sometimes small red spots on the vaginal walls or cervix

For people with penises, symptoms might include discharge from the urethra, burning after peeing or ejaculation, and general irritation.

How Trich spreads from person to person

Trich spreads through sexual contact—vaginal, oral, or anal sex—with vaginal sex being the most common route. The parasite can survive briefly in bodily fluids, so sharing sex toys without cleaning them can also pass it along. The tricky part? People without symptoms can still spread it.

Using condoms can lower the risk, but they’re not 100% foolproof since the parasite can infect areas condoms don’t cover.

How to test and get the right diagnosis

Getting a proper diagnosis matters because BV and trich look similar but need different treatments. Modern testing makes it easy to figure out exactly what’s going on—or if you have both infections at the same time.

How to test for BV

Getting the right diagnosis for BV is all about spotting bacterial imbalance in your vagina. Your healthcare provider has a few ways to do this. The classic approach is a pelvic exam where they take a vaginal sample and check it under a microscope for “clue cells,” which are vaginal cells covered in bacteria.

They might also do a "whiff test," adding a bit of potassium hydroxide to see if that signature fishy smell shows up. A vaginal pH above 4.5 can also suggest BV.

At-home vaginal microbiome tests are another option. They can detect changes in BV-related bacteria, letting you take control of your testing from home. Either way, the goal is the same: understand what’s going on so treatment hits the mark.

How to test for Trich

Trichomoniasis testing focuses on spotting the tiny parasite Trichomonas vaginalis. Traditional methods include a pelvic exam where a sample is checked under a microscope for moving parasites, though this only catches most infections, so you could miss something.

The gold standard is nucleic acid amplification testing (NAAT), which detects the parasite’s genetic material. Accuracy is way higher, and you can use a vaginal swab or urine sample. Results typically arrive in a few days, and some point-of-care NAATs can even give results in under an hour.

At-home STI testing kits now often use NAAT technology too. You collect the sample yourself and mail it to a lab, with results reviewed by a clinician who can provide treatment if needed. This makes testing super convenient, private, and quick—perfect for taking care of your sexual health on your own terms.

When to get tested

Get tested anytime you notice unusual vaginal symptoms, even if they seem mild. Co-infections happen, so if you’ve had one infection, it’s worth checking for others.

People diagnosed with trich should also screen for other STIs, including HIV, since trich can increase the risk of transmission. Regular screening is smart if you’re sexually active, especially with multiple partners or if your partner does.

Pregnant? Testing is extra important since both BV and trich can affect your pregnancy.

How to treat each issue

Both BV and trich respond really well once you know what you’re dealing with. The trick is using the right medication for the right infection and finishing the full course, even if symptoms start improving fast.

How to treat BV

BV treatment typically requires prescription antibiotics. Oral metronidazole twice daily for seven days is the classic choice.

If you prefer something local, metronidazole gel inserted vaginally for five nights can help limit side effects like nausea. Clindamycin cream is another option, especially if you can’t take metronidazole.

When you’re using clindamycin, pay attention (and reach out for help) if you notice any of the following:

• Anything that feels like an allergic reaction (itching, rashes, swelling)
• Severe diarrhea and fever
• Weird vaginal discharge (like, weirder than what you were already dealing with)

There’s also secnidazole, a single-dose granule packet you mix with food—super simple and convenient.

Unfortunately, secnidazole could potentially cause vaginal yeast infections. You may also want to get in touch with your healthcare provider if you notice:

• Weird taste changes
• Headaches
• An upset stomach—pain, nausea, vomiting, diarrhea

During treatment, avoid alcohol with metronidazole or tinidazole to prevent intense nausea and vomiting, flushing, headaches, and other serious symptoms.

Other side effects of metronidazole and tinidazole can include a metallic taste, upset stomach, or sometimes a yeast infection as well. Some people like to take probiotics during and after treatment to help support their healthy vaginal bacteria.

Wisp treatment options are available only after consultation with a licensed medical professional. You should consult with your healthcare provider before starting a new supplement or treatment regimen. Individual results may vary.

How to treat Trichomoniasis

Trich treatment targets the parasite with prescription antibiotics, too. The standard approach is a single large dose of metronidazole or tinidazole (2 grams), though some providers may prescribe metronidazole twice daily for seven days. Tinidazole is sometimes easier on your stomach and may even have slightly higher cure rates.

Single-dose treatment is convenient—no juggling multiple pills. For rare, resistant cases, higher doses or longer courses might be needed. During treatment, avoid sex until you and all partners finish the course and symptoms are gone, usually about a week.

Why your partner needs treatment, too

Here’s where BV and trich are very different.

For trich, all sexual partners need treatment. If even one person skips it, the infection bounces back. Expedited partner therapy makes it simple—medication can be prescribed without requiring everyone to come in for testing.

BV is trickier. Traditionally, male partners weren’t treated since they can’t carry BV in the same way. New research suggests that treating male partners may help lower recurrence for women, so some providers offer partner therapy for male partners, too. Female partners of women with BV might benefit from testing and treatment if they have symptoms.

The bottom line: keep communication open with your partners about diagnosis and treatment. That way, everyone gets the care they need and you can stop reinfections from happening.

Know what’s going on down there and take charge

BV and trich may throw similar symptoms your way—unusual discharge, odd smells—but they’re two very different characters. BV happens when your natural vaginal bacteria get out of balance, while trichomoniasis is a parasite that spreads through sex. The good news? Both clear up with the right antibiotics—but only if you get the right diagnosis first.

Don’t let awkwardness hold you back. These infections are super common, totally treatable, and nothing to be embarrassed about. With Wisp, you can get discreet at-home testing and online treatment, so there’s no in-person waiting rooms, no judgment, and no hassle. Take care of your sexual health on your schedule—because when it comes to your vagina, you call the shots.

Ready to get tested and treated from home? Visit Wisp for an online consult and get started today.

This blog post is for informational and educational purposes only and should not be taken as professional advice. Always consult with a qualified professional before making any decisions based on the information provided here.