It’s possible to get genital herpes from oral sex whether or not the other person has a cold sore (a small painful blister that forms on or near the lips).

How Can a Cold Sore Cause Genital Herpes?

Two viruses can cause genital herpes: herpes simplex virus type 1 (HSV-1) and HSV type 2 (HSV-2).

HSV-1 tends to cause sores around the mouth (cold sores) and HSV-2 often causes sores on the genitals. But these viruses can cause sores in either place.

If someone has oral sex with a person who has HSV-1, the virus could spread and cause genital herpes. HSV-1 doesn’t always cause cold sores though, so you may not know if someone has the virus. That’s why it’s important to always use protection when having sex.

How Can I Avoid Genital Herpes?

Sexually transmitted diseases (STDs) like genital herpes can spread through oral, vaginal, or anal sex; using fingers; or with other sexual contact. So, use a condom, finger condom, or dental dam each time you have sex. If either partner has a sore, it’s best to not have sex until it clears up.

Keep in mind that STDs can be on areas of skin that protection doesn’t cover. So, the only way to fully avoid getting STDs is to not have sex.

What Else Should I Know?

To help prevent both STDs and pregnancy, use condoms or other barrier methods (birth control that helps “block” STDs and sperm) along with birth control like the Pill. If you have questions about which kind is right for you, talk with your doctor. You can also go to a health clinic like Planned Parenthood.