Mycoplasma genitalium (MG or MGen for short) is a sexually transmitted infection (STI) caused by bacteria. Up to one in 50 adults are thought to have MG at any point. Often, they do not have symptoms. 

Most MG infections do not cause any health problems and can be easily treated. However, it can sometimes lead to long-term complications.

If you’re worried you have MG or another STI, talk to us. You are doing the best thing by getting diagnosed and treated. We understand it might feel awkward, but we are here to help you. We will always treat you with kindness and respect. 

You’re unlikely to have symptoms with MG. If you do they can include: 

  • pain when you pee
  • unusual discharge from your penis or vagina
  • discomfort or discharge from your bottom (anus) if you’ve had anal sex

If you’re a man, you may also get:

  • pain in your testicles (balls)

If you’re a woman you may also get:

  • pain in your tummy or pelvis
  • pain during sex
  • bleeding after sex or between periods

You can get MG from having sex with someone who has the infection. It can be passed on through vaginal, oral or anal sex. You can also get it from sharing sex toys.

You might not know if the person you’re having sex with has MG. If you’ve had MG once, you can still get it again.

MG is tested with a pee sample or by wiping an area with a small swab (swab test).

If you have symptoms of MG, or have had sex with someone who has MG, call us on 0800 328 3383 or find a clinic, so we can help you. 

MG is treated with antibiotics. You will be asked to come back for a second test 5 weeks after you’ve finished treatment. This is to make sure the antibiotics have worked and the infection is gone.

If you have symptoms, they should get better a few days after starting your treatment. You should still wait until you’ve had the all-clear from your second test before having sex again.

Tell us if you are pregnant or breastfeeding as you might need a different type of antibiotic.

If you test positive for MG, or any STI, you will need to tell your partner and any recent partners so they can get tested too. This means anyone you have had sex with within the past 3 months. 

We know this might be awkward, so we can contact them for you. We do not give your name. You can also call us on 0800 328 3383 for details of this service if you're being treated elsewhere.

MG usually causes no long-term problems. In some cases though, it may lead to pelvic inflammatory disease (PID), ectopic pregnancy and infertility in women. If you’re a man it can spread and cause epididymo-orchitis, which is an inflammation of your testicles.

While complications are not likely, it’s best to make sure you get tested and treated. 

You can help avoid getting MG and other STIs by using condoms each time you have sex. This includes vaginal, oral and anal sex, and when using sex toys. 

Find out more about protecting yourself from STIs.