This affects both men and women, and any age group.  It is the most common bacterial STI amongst young men and women, affecting 1 in 12 sexually active young people under the age of 25.  Often there are no symptoms so people don’t know they have it .  

How you get it:  

  • Unprotected vaginal or anal penetrative sex 
  • Oral sex  
  • Sharing sex toys that aren't washed or covered with a new condom each time they're used 
  • The genitals coming into contact with another person’s genitals – this means you can get chlamydia from someone even if there is no penetration, orgasm or ejaculation 
  • Infected semen or vaginal fluid getting into your eye 


  • Most of the time, none, but sometimes pain when peeing (male), lower abdominal pain (female) or discharge from the vagina or penis. 

If it’s not treated 

  • It can lead to pelvic inflammatory disease in women; this can lead to infertility in both men and women  
  • Men can get painful swollen testicles
  • Men can also get a rare form of arthritis (SARA- Sexually Acquired Reactive Arthritis) 


  • Is a simple course of antibiotics - this is generally 1 tablet twice a day for one week.