There are more than 20 known types* of sexually transmitted infections (STIs.) Chlamydia and gonorrhea are the most common STIs in Canada, especially in teenagers and young adults.**
All STIs have one thing in common: they are spread through sexual contact, including vaginal, anal and oral sex.
This section offers information about the most common STIs - for example the signs and symptoms and treatment. Visit our HIV/AIDS section for specific information about HIV/AIDS, including what to do if you're HIV positive and HIV and pregnant.
Common Sexually Transmitted Infections ( STIs) 