What is the difference?
Bacterial vaginosis vs Trichomoniasis
Both can cause unusual vaginal discharge with a fishy smell, so they are easily mixed up. Bacterial vaginosis is a shift in the vagina's own bacteria and is not classed as an STI, while trichomoniasis is an STI caused by a tiny parasite.
General information, not medical advice. For advice about your own situation, talk to a clinician, pharmacist or sexual health clinic.
Bacterial vaginosis
Bacterial vaginosis (BV) is a common condition in which the normal balance of bacteria in the vagina shifts, often causing thin grey-white discharge with a fishy smell.
Full entryTrichomoniasis
Trichomoniasis is a common STI caused by a tiny parasite, often without symptoms, and is cured with a course of antibiotics.
Full entrySide by side
In short
Similar discharge, different cause: BV is a bacterial imbalance, trich is an STI. A swab at a clinic tells them apart, so self-treating on a guess is not a good idea.
What they have in common
Both are common, often cause no symptoms at all, are usually treated with antibiotics such as metronidazole, and can raise the risk of other STIs and of pregnancy complications if left untreated.
Sources
- NHSBacterial vaginosis
- NHSTrichomoniasis
- Planned ParenthoodVaginitis
More comparisons
- Bacterial vaginosisvsThrushA fishy smell points more towards BV, itching more towards thrush, but symptoms overlap, so it is worth getting them checked by a pharmacist, doctor or sexual health clinic.
- Affirmative consentvsEnthusiastic consentAffirmative consent is about getting a clear yes; enthusiastic consent goes a step further and cares whether that yes is truly wanted.
- Anxious attachmentvsAvoidant attachmentAnxious attachment leans in and needs reassurance; avoidant attachment leans out and needs space. Both people usually care deeply; they simply protect themselves in opposite ways.
- AsexualvsAromanticAsexual answers "do I feel sexual attraction?"; aromantic answers "do I feel romantic attraction?". A person can be one, both or neither.
Last reviewed 16 October 2026. Spotted a mistake?