What are STDs or STIs?

Sexually transmitted diseases (STDs) or sexually transmitted infections (STIs) are caused by infections that are passed from one person to another during sexual contact.

These infections often do not cause any symptoms. Medically, infections are only called diseases when they cause symptoms. That is why STDs are also called "sexually transmitted infections." But it’s very common for people to use the terms "sexually transmitted diseases" or "STDs," even when there are no signs of disease.

There are many kinds of sexually transmitted diseases and infections. And they are very common — more than half of all of us will get one at some time in our lives.

The good news is we can protect ourselves and each other from STDs. Practicing safer sex allows you to reduce your risk of getting sexually transmitted diseases. And if you've done anything that puts you at risk of infection, getting tested allows you to get any treatments you may need. Find out if you should get tested for HIV, chlamydia, or gonorrhea, three dangerous STDs, with The Check.