This article was last reviewed on
This article waslast modified on 1 February 2019.

There are more than 20 known sexually transmitted diseases (STDs). Some of them will cause symptoms that should be brought to the attention of a doctor immediately. However, some of these STDs can be "silent" — a person could have the disease but might not notice any symptoms of the infection. Therefore, it is important to be tested for STDs if you take part in unprotected oral, genital, or anal sex.

The most common STDs are listed below:

  • Gonorrhoea. This bacterial infection at first may cause a slight discharge from the vagina, penis, or anus. However, 50% of women and 10% of men with gonorrhoea have no symptoms at all. If the infection is not treated, it can lead to sterility and other complications. Gonorrhoea can be treated with antibiotics.
  • Chlamydia. Chlamydia trachomatis is often called "the silent epidemic" because infections are common yet many people do not realize that they are infected. Only one in four of infected people have symptoms of a slight discharge and stinging on passing urine. It is the commonest STD in the UK. This bacterial disease is easily cured with antibiotics but can have serious health consequences if left untreated.
  • Syphilis. Syphilis is a bacterial infection that can be easily missed. The first symptom is a painless blister or sore that will disappear on its own, but the infection can be passed on to others for up to eighteen months. Syphilis can be treated with antibiotics. However, if left untreated, the disease can spread throughout your body over the course of many years and cause considerable organ damage.
  • Trichomonas. Trichomonas vaginalis is a microscopic parasite that may or may not cause symptoms of watery discharge and stinging on passing water. Treatment is available.
  • Human papillomavirus (HPV). This virus can infect the genital area, causing genital warts (condylomata). Some types of the virus have been associated with cervical cancer. Early detection with cervical smear testing can limit the risk of cancer.
  • Genital herpes. This virus causes recurrent, periodic outbreaks of sores in the genital region and remains in your body for life. However, there are anti-viral therapies available that can shorten the duration of symptoms.
  • Hepatitis B and Hepatitis C. These are viral infections that can be transmitted through sexual contact. Hepatitis B and C affect the liver and can severely damage it. Treatment with interferon is available, but this drug therapy may have serious side effects.
  • Human Immunodeficiency Virus (HIV). HIV is associated with AIDS. This virus attacks and destroys certain white blood cells (T-helper lymphocytes) that are involved in the immune system. As the number of these cells is reduced, the ability of your body to fight off infections also decreases. This eventually results in death. Although there is no cure, early detection allows for treatment with anti-viral therapies that can help to prolong life.

You can refer yourself to any Sexual Health Clinic in the UK to receive free, confidential testing and treatment. Your GP is not informed without your permission. For any sexually transmitted disease, an infected person should inform their recent sexual partner(s) so that they may be treated as well. Clinic staff will advise you how best to do this, but it is not compulsory.