Updated August 2025
Chlamydia is a sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis.
It can take two to six weeks or longer for symptoms to appear. About 70% of women and 50% of men infected with chlamydia have no symptoms. However, they can still pass the infection on to their sexual partner(s) without knowing.
Women may have increased vaginal discharge or irritation. Other symptoms may include pain during urination, bleeding during or after sexual intercourse, abnormal spotting or bleeding between periods, pain in the lower abdomen or pain during sexual intercourse. The symptoms are sometimes mistaken for a bladder or vaginal infection.
Men may have a burning sensation when urinating, a discharge from the penis or itching around the urethra (opening to the penis). These symptoms may come and go.
Both men and women can get chlamydia in the throat from oral sex. This usually does not cause any symptoms. Chlamydia in the rectum can cause rectal discharge, bleeding, anal itching, soreness, or painful bowel movements. There can also be no symptoms.
Chlamydia can be passed on through unprotected oral, vaginal, or anal sex from a person who is infected. It can sometimes cause eye infections when hands infected with anal, penile, and vaginal fluids touch the eye. An infected person can pass on the infection at any time until they are properly treated with antibiotics. It can also be passed from an infected mother to the baby during birth.
Untreated chlamydia can live in the body for months or even years.
A doctor or nurse can take a sample by swabbing the infected area (cervix, vagina, urethra, rectum, or throat). Urine testing is also commonly used to diagnose both men and women. Samples are then sent to the laboratory for testing.
In some cases, the doctor or nurse will advise a follow-up test to make sure the infection is cured. Follow-up testing should be done 3 weeks after completing treatment.
Untreated chlamydia in women may lead to a condition called pelvic inflammatory disease (PID). It is a serious infection of the uterus, the fallopian tubes, and the ovaries. PID can cause ongoing (chronic) pelvic pain. Untreated PID can cause damage to the fallopian tubes, making it hard to get pregnant and increasing the risk of having an ectopic pregnancy. An ectopic pregnancy is a life-threatening condition where the fertilized egg grows outside of the uterus, usually in the fallopian tubes. Treatment is needed to stop the pregnancy.
Some men may develop swelling and pain in their testicles, a condition called epididymitis. It is also possible for men with untreated chlamydia to have blocked tubes so the sperm cannot pass, resulting in infertility.
Infants who are born to mothers with untreated chlamydia may get the infection as they pass through the birth canal. Infants may develop an eye infection or pneumonia.
Chlamydia is treated with antibiotic pills. The most commonly used antibiotics include azithromycin and doxycycline. It is important for you and your partner(s) to take all the medication you are given, even if you do not have symptoms or if the symptoms have disappeared. Do not have sex while you and your partner(s) are on the medication and for 7 days after you finish, even with a condom.
Here are a few important points to remember
All sexual partners within the past 60 days should be tested and treated. If you have not had sex in the past 60 days, then your last sexual partner should be tested and treated. Tell your partner(s) that having no symptoms does not mean there isn’t an infection.
If you do not want to tell your partner(s), a public health nurse can notify them for you. Your name will be kept confidential.
Call the Sexual Health Infoline Ontario at 416-392-2437 (1-800-668-2437) or visit toronto.ca/health
Safer sex: To reduce your risk of getting a sexually transmitted infection (STI), use a condom every time you have vaginal, anal or oral sex.