Whether you're clued up or don't have a clue, we're here to talk about STIs

We’ve done the research on eight of the most common types of STIs, so you don’t have to. It’s time to talk more about them and swot up on how they can be detected, treated and, most importantly, how to avoid catching them.

What is an STI?

An STI is a sexually transmitted infection that can be passed from one person to another through sexual contact, usually vaginal, anal or oral sex. The list of STIs is pretty lengthy, so we’re here to help you understand some of the most common ones to be aware of...

The 8 types of STIs you need to know about

All STIs are different, but one thing’s true – if you have an STI, you shouldn’t have sex until the STI has cleared up to avoid infecting your partner. If you think you've got an STI, go for a check-up at a sexual health clinic as soon as possible.

Anyone who has sex can get an STI, so you should always use a condom to help protect against them.


Probably the most well-known STI, especially amongst younger adults, which is why it’s recommended that sexually active adults under 25 (in the UK) get routinely tested for it once a year or when you change partners. Anyone of any age can visit a GP or make an appointment at their nearest sexual health or GUM clinic for a free confidential chlamydia test. You can also find out if you’ve got chlamydia by using the Boots Online Doctor Chlamydia Home Test Kit – there’s a test kit for women, and one for men.*

What are the symptoms: most people don’t actually get symptoms, so it’s important you get routinely tested for chlamydia if you’re sexually active, and especially if you change partners regularly. If you do get symptoms, they can include unusual discharge for women, stomach pain, bleeding after sex, bleeding between periods and for men, swelling in the testicles.

How do you catch it: it might seem like an obvious answer – through unprotected sex, but you can also get it from sharing sex toys (only if the person who used it already has chlamydia), if your genitals come into contact with your partners, or infected semen or vaginal fluid gets into your eye.

How do you treat it: your GP or your nearest sexual health or GUM clinic will be able to prescribe an antibiotic to be taken over three or more days. Make sure you finish the course and take the antibiotic as instructed for the treatment to be effective. You can also get antibiotics to treat a chlamydia infection through the Boots Online Doctor – Chlamydia Treatment Service.*

What happens if it’s left untreated: it can spread to other parts of your body and lead to long-term health conditions like infertility.

Genital herpes

These look like small blisters that burst, leaving red open sores that usually appear around your genitals, anus, thighs or bum. They’re extremely easy to pass on and there’s no cure once you catch it. This is because the virus stays in your body, meaning that symptoms can come and go.

What are the symptoms: symptoms include tingling, burning or itching around your genitals, pain when you pee and in women, vaginal discharge that’s unusual for you. They might not appear for weeks or even years after you catch herpes. Once you get symptoms, they should clear up by themselves, but are likely to reoccur. 

How do you catch it: as well as through sex, you can get it from a cold sore that touches your genitals. It can also be transferred from fingers that have touched a vagina or penis that’s infected, or by sharing sex toys with someone who already has herpes. You can still catch herpes from someone who has it even when there are no visible sores or blisters.

How do you treat it: as there’s no cure, you can’t get rid of the virus. However, you can treat the blisters by keeping the area clean with salt or plain water to help prevent them from becoming infected. Apply an ice pack wrapped in a flannel to soothe any pain. You can also get fast-acting medicine to see off your sores or to help with the pain through the Boots Online Doctor – Genital Herpes Treatment Service.*

If you have genital herpes during pregnancy, there’s a risk your baby could develop neonatal herpes, which can be fatal. Most babies recover with the right treatment, so make sure you see your midwife or GP as soon as possible if you think you have genital herpes in pregnancy.

Genital warts

These look like one or more painless growths or lumps that appear around your vagina, penis or anus. There’s no cure for genital warts, but it’s possible for your body to clear the virus (HPV) over time.

What are the symptoms: in addition to the lumps, you can also get itching or bleeding from your genitals or anus, or you may notice a change to your normal flow of pee (for example, if it goes sideways when it didn’t before).

How do you catch it: skin-to-skin contact, including vaginal and anal sex, sharing sex toys with someone who already has genital warts, and oral sex (but this is a rare way to catch it).

How do you treat it: depending on what your warts are like, you could be offered one of the following treatments – cream or liquid, surgery that involves cutting, burning or using a laser to remove the warts, or freezing them off. You can also get treatment for genital warts through the Boots Online Doctor – Genital Warts Treatment Service.*

How is it different from genital herpes: while the name is similar, it’s actually very different. Genital warts can come from human papillomavirus and genital herpes comes from a different virus entirely, herpes simplex virus type 1 or type 2.

Human papillomavirus (HPV)

HPV is the name of a very common group of viruses that affect the skin – most people will get some type of HPV in their lives. They usually don’t cause any problems, but some types can cause genital warts or cancer.

What are the symptoms: HPV has no symptoms, so you may not know if you have it.

How do you catch it: you can get HPV from skin-to-skin contact of the genital area, vaginal, anal or oral sex, or by sharing sex toys with someone that has it. You don’t have to have sexual contact with a lot of people to get HPV. You can get HPV the first time you're sexually active.

How do you treat it: there's no treatment, and most HPV infections are cleared by your body within two years. If HPV causes genital warts, your GP will be able to prescribe treatment for these, or you can access the Boots Online Doctor – Genital Warts Treatment Service.*

Some types of HPV can cause abnormal changes in the cells that can sometimes turn into cancer, including cervical cancer, anal cancer, cancer of the penis, vulval cancer, vaginal cancer and some types of head and neck cancer. Whilst you can’t fully protect yourself against HPV, the HPV vaccine helps protect against genital warts and cervical cancer, as well as some other cancers caused by HPV. It doesn’t protect against all types of HPV.

In England, girls and boys aged 12 to 13 years are routinely offered the first HPV vaccination when they're in school (Year 8). The second dose is offered six to 24 months after. It’s important to have both doses to be properly protected. If you’re eligible and miss the HPV vaccine offered in Year 8 at school, it’s available for free on the NHS up until your 25th birthday for girls born after 1 September 1991 and boys born after 1 September 2006.

Gonorrhoea (or the clap)

The bacteria that causes this STI is mainly found in discharge from the penis and in vaginal fluid, and can infect the cervix, the urethra, the rectum and even the throat or eyes (but this is uncommon).

You can find out if you’ve got gonorrhoea by using the Boots Online Doctor Home Test Kit – there’s a test kit for women, and one for men.*

What are the symptoms: about one in 10 infected men and five in 10 infected women don’t experience obvious symptoms, which means it can go untreated for a while. If you do get any, they’ll look like this – thick green or yellow discharge from the vagina or penis, pain when urinating, and bleeding between periods in women.

How do you catch it: it’s easily passed through unprotected sex or sharing sex toys (that haven’t been washed or covered with a new condom each time they are used) with someone who has it.

How do you treat it: if you visit your GP, it’s usually treated with a single antibiotic injection and a single antibiotic tablet or capsule.

What happens if it’s left untreated: it can lead to serious long-term health problems like pelvic inflammatory disease (infection of the womb, fallopian tubes and ovaries) in women, or infertility.

If you’re pregnant, the infection can also be passed onto your baby, and without treatment can cause permanent blindness in a newborn. Ensure you see your GP straight away if you have gonorrhoea or think you do, as it’s important to get tested and treated before your baby is born.

Pubic lice (or crabs)

These are tiny insects that live on human body hair, such as pubic hair, underarm and leg hair, hair on the chest, abdomen and back, facial hair, and eyelashes and eyebrows (but this is quite rare).

What are the symptoms: itching in the areas where pubic lice live, inflammation and irritation, black powder in your underwear, blue spots or small spots of blood on your skin (these are caused by the lice biting you).

How do you catch it:
 they spread through close bodily contact, most commonly through sexual contact.

How do you treat it: you should visit your GP who will be able to advise you about which treatment you should use, which will usually be an insecticide cream, lotion or shampoo.


It’s a bacterial infection that, if left untreated for years, can spread to the brain or other parts of the body and cause serious long-term problems.

What are the symptoms: small, painless sores on the penis, vagina or anus (they can also show up in your mouth), blotchy red rashes that appear on the palms of the hands or soles of feet, small skin growths, white patches in the mouth, tiredness, headaches, joint pains, a fever and swollen glands in your neck, groin or armpits – yep, that’s quite a lot! But some people can have no symptoms at all.

How do you catch it: usually by having vaginal, anal or oral sex, or by sharing sex toys with someone who’s infected. Pregnant women can also pass it onto their unborn baby.

How do you treat it: it won’t go away on its own, so you need to see your GP who will test you and give you medicine to help reduce the risk of it spreading or causing serious problems for you later on.


This STI is caused by a tiny parasite called Trichomonas vaginalis (TV), and symptoms usually develop within a month of infection. However, half of people don’t actually get any symptoms, which is why routine check-ups are essential.

What are the symptoms: abnormal discharge from the vagina or penis, producing more than usual that has an unpleasant fishy smell, soreness and itching around the vagina (your thighs might become itchy, too) or head of the penis, and pain or discomfort when peeing, having sex or ejaculating.

How do you catch it: it’s usually spread by unprotected sex or by sharing sex toys with someone who already is – it can’t be passed on through oral or anal sex.

How do you treat it: your GP will give you a course of antibiotics. Make sure you finish the whole course to ensure that the infection clears up. You can also get treatment if you or your partner have tested positive for trichomoniasis with a test kit through the Boots Online Doctor – Trichomoniasis Treatment Service.*

All of these STIs are pretty common, so make sure to wrap it up and don’t be afraid to tell your partner to either. We all need to be responsible for our health, which is why we should start talking openly about sexual health, get regularly tested for STIs and practice safe sex.

If you need more questions answering about your sexual health, head to Ask Brook. If you’re at all concerned about your sexual health, or you think you have an STI, speak to your GP or visit your local GUM clinic as soon as you can.

*Subject to availability and access to prescription only medicine is subject to a consultation with a clinician to assess suitability. Charges apply.