A sexually transmitted infection, or STI, is an infection that can spread through sexual contact. Some people still use the term STD, but STI is often preferred because a person can have an infection without obvious symptoms. If you are worried about a possible STI exposure, it is understandable to feel anxious or unsure about what to do next. The most important thing to know is this: many STIs are treatable, some are curable, and testing is the only way to know for sure. Wha