Newsbeat's guide to Sexually Transmitted Infections
There needs to be more investment in drugs that treat STIs like gonorrhoea, a leading sexual health expert has told Newsbeat.
Diagnosis of the infection has gone up by 25% in the last year and there are worries there's not enough funding to develop new treatments.
STIs can be caught when people have unprotected oral, anal and vaginal sex.
Find out more about some of the most common STIs below.
Caused by the HPV virus, these small fleshy growths, bumps or skin changes appear around the genital or anal area.
They're the second most common infection after chlamydia. Warts can appear on their own or in clusters, giving a cauliflower appearance.
They are usually painless but may be uncomfortable if around the anus.
Symptoms occur normally two or three months after infection, sometimes up to a year, and a person can be infected just by skin-to-skin contact as well as penetrative sex.
They don't pose a serious threat to health but can cause psychological distress.
Creams or lotions, or sometimes a laser on harder warts.
Women - about 70-80% don't show any symptoms.
The most common ones though can include pain when urinating, change in vaginal discharge, pain or bleeding during or after sex, heavier periods, lower abdominal pain.
Men - half of men don't get any symptoms but those who do may get pain when urinating, discharge from the penis and testicle pain.
Chlamydia can also affect the rectum, eyes or throat.
Women - if untreated it can cause PID (inflammation of the womb with increases the risk of infertility and miscarriage).
It can also cause inflammation of the cervix (cervicitis).
Men - urethritis, which is inflammation of the urine tube that runs along the penis. If untreated, chlamydia may also cause infertility in men.
Antibiotics - 95% of people can be cured if they take them correctly.
Caused by the herpes simplex virus (which also causes sold sores on the mouth), infected people may get painful red blisters in the genital area, thighs and buttocks.
Pain when urinating, vaginal discharge, fever and aches and pains are also common.
Symptoms might not appear for months or even years after being infected. After the first outbreak goes away it can come back time to time - but is usually less severe.
The blisters can sometime become infected and cause a skin infection in other areas.
It can also cause some pregnancy problems, depending on when a woman has the virus. The virus may also be passed to the baby.
Antiviral tablets are often prescribed for first-time sufferers.
Women - vaginal discharge which may be green or yellow in colour. Pain when urinating.
Pain in the lower abdomen and bleeding between periods, or heavier periods.
Men - discharge from the penis that may be white, yellow or green. Pain or burning when urinating. Swelling of the foreskin.
Symptoms usually appear within a week of being infected but sometimes may not show up until months later.
The infection can also affect the eyes, rectum or throat if semen or vaginal fluid comes into contact with these areas.
If treated early gonorrhoea is unlikely to give any long-term problems.
But if left without treatment it can be serious. Women can get pelvic inflammatory disease (PID) which can also lead to infertility.
Men can get infections in the testicles and prostate and that can also affect fertility.
A course of antibiotics through an injection or pill. Quick treatment is vital.
Source - NHS Choices