Sexually transmitted infections (STIs) can be passed on when you have unprotected sex or close sexual contact with someone who already has an STI.
Using a male (external) or female (internal) condom or dental dam every time you have sex is the best way to prevent STIs. Getting tested regularly for STIs will also help you to look after your sexual health.
Most STIs can be easily treated, however without treatment they can sometimes lead to more serious health problems.
If you think you have an STI, it’s important to see a healthcare professional rather than trying to diagnose it yourself, as symptoms can vary from person to person.