A sexual infection, also known as a sexually transmitted infection (STI) or sexually transmitted disease (STD), is an infection that is spread through sexual contact. This can include vaginal, anal, or oral sex. Common sexual infections include chlamydia, gonorrhea, syphilis, herpes, HPV, and HIV. These infections can be transmitted through unprotected sexual activity with an infected partner and can have serious health consequences if left untreated. It is important to practice safe sex and get tested regularly for STIs to prevent the spread of infection and protect your health.