Sexual transmitted diseases

Synonyms: STD, Sexual transmitted infections (STIs)

Medical Specialties: Obstetrics/gynecology, Preventative medicine, Urology

Clinical Definition

STDs, or sexually transmitted diseases, are infections that spread through sexual activity with someone who is already infected. They may be transmitted by mouth, anus, vagina or penis. Many of these infections can be treated with antibiotics. 

In Our Own Words

Sexually transmitted diseases (STDs) are infections and viruses spread through unprotected oral, anal or vaginal sexual activity. Both having multiple partners and practicing unprotected sex increase the risk of transmission. Using a latex or polyurethane condom is considered the most effective method for reducing transmission.


Left untreated, STDs may lead to infertility because they can cause scarring or damage to the fallopian tubes in women and scarring or blockage of the ejaculatory ducts in men. 

Relevant Conditions
  • AIDS
  • Infertility
  • Chronic pelvic pain
  • Epididymitis
  • Reiter’s syndrome
  • Pelvic inflammatory disease (PID)
Side Effects
  • Bumps, sores or warts near the mouth, anus, penis or vagina
  • Swelling or redness near the vagina or penis
  • Painful sex
  • Painful urination
  • Discharge for the penis or vagina
Share this article
  • Cleveland Clinic. “Sexually Transmitted Diseases: An Overview.” Accessed August 2013.
  • Centers for Disease Control and Prevention. “Incidence, Prevalence, and Cost of Sexually Transmitted Infections in the United States.” February 2013. Accessed August 2013.
  • Harvard Health Publications. “Conditions that affect fertility.” Accessed September 2013.
  • Centers for Disease Control and Prevention. “Sexual Transmitted Diseases (STDs): Diseases & Related Conditions” Updated May 2013. Accessed August 2013.
  • Harvard Health Publications. “Six ways you can help your immune system.” Accessed August 2013.
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