SummaryRead the full fact sheet
- Trichomonas (also known as trichomoniasis and 'trich') is a sexually transmissible infection (STI).
- Many people with trichomonas do not experience any symptoms.
- Trichomonas may cause a yellowy green, ‘frothy’ discharge that is often accompanied by an unpleasant odour, vaginal or vulval itching and/or a burning sensation.
- The infection can be treated with antibiotics.
- Avoid sex or use condoms until the infection has been treated.
Trichomonas (or trichomoniasis) and its causes
Trichomonas (also known as trichomoniasis or 'trich') is caused by the organism Trichomonas vaginalis.
Trichomonas is detected more often in people with vaginas than those who have a penis.
Many people don’t have any symptoms of infection. When symptoms are present, they may include:
- a yellowy green, ‘frothy’ discharge
- an unpleasant odour
- vaginal or vulval itching and burning.
People with a penis usually don’t develop symptoms, but they may be carriers of the infection. Some may experience discharge from the penis and burning during urination.
If you have a vagina, a vaginal examination and swab is required.
If you have a penis, a swab is taken if discharge is present. Otherwise, a urine sample can be collected and tested.
Antibiotics are used to treat trichomonas.
Standard treatment for trichomonas is:
- metronidazole (Flagyl) – a single dose, 400 mg oral tablet twice daily for 7 days, taken with food (for people with a vagina)
- metronidazole – 2 g tablet single dose (for people with a penis).
Avoid drinking alcohol during treatment and for 48 hours after taking metronidazole.
Possible side effects of trichomonas treatment
This medication may cause:
- nausea or an upset stomach
- a metallic taste in your mouth, which will disappear soon after the treatment is completed.
Preventing trichomonas reinfection
If you have trichomonas, all your sexual partners need to be treated – even if you have no symptoms.
Avoid sexual contact until one week after treatment starts and any symptoms have resolved. (Remember, if your partner starts treatment after you, don't have sex until a week after the date they started.)
Managing recurrent trichomonas
Occasionally, trichomonas may recur after the initial infection has been treated.
If this happens, see your GP, who may prescribe a longer course of treatment.
Letting partners know you have trichomonas
When you've been diagnosed with an STI like trichomonas, all of your sexual partners (regular and casual) from the last few months needs to be informed, tested and treated.
If they don’t know, they could reinfect you or infect someone else if they are not treated. They may also experience serious problems later on.
Most people will appreciate being told they may have an infection and it is an important step in preventing further infection in the community.
Your local GP and sexual health centre can help you inform your partners and let them know that they need a test. This process is called ‘partner notification’. It can be done anonymously, and your confidentiality is always respected.
Where to get help
- Your school nurse or school welfare coordinator (Some secondary schools provide access to an adolescent health trained GP on site)
- Your pharmacist (including after hours )
- . To book an appointment call SHV Melbourne CBD Clinic: or call SHV Box Hill Clinic: or (free call): . These services are youth friendly
- Tel. or .
- – visit Melbourne Sexual Health Centre's GP partner clinics for STI check-ups and treatment
- (formerly Victorian AIDS Council) Tel. or
- Tel. Or
- , Wodonga Tel. or
- (throughout Victoria)
- Tel: is a statewide phone service for information about sexual health as well as contraception and pregnancy options