Chlamydia is a sexually transmitted disease (STD) caused by the bacterium Chlamydia trachomatis. The bacterium can infect the reproductive tract of males or females and may cause symptoms like fluid discharge from the vagina or penis. However, many people with chlamydia experience no symptoms at all.

Chlamydia is one of the most common STDs in the United States and it is the most common bacterial STD. Approximately one million chlamydia infections are reported each year and many more likely occur without being reported. The disease can affect people of any age but it is most common in teenagers.

Chlamydia can be easily treated with antibiotics, but many people may not know that they have the disease. If left untreated, chlamydia can lead to serious health problems, including infertility.