If one partner has an untreated sexually transmitted infection, it may be passed on during oral sex (licking a vagina). HIV is not usually passed on this way, but herpes simplex virus, syphilis and gonorrhea may be.
Cold sores around the mouth can transmit herpes if they touch the vagina. Similarly, syphilis sores around the genitals or mouth could pass on the infection to another person during oral sex. If vaginal secretions are infected with gonorrhea or some other STIs, the infection could be transmitted during oral sex, especially if there are any sores, cuts or ulcers around the lips or mouth.
In theory, HIV could be passed on if a woman had infectious levels of HIV in her vaginal secretions or menstrual blood. However the mouth is actually quite an inhospitable environment for HIV, making infection due to licking a vagina highly unlikely. Scientists have not found any well-documented cases of transmission through this route. (Similarly, the risk through sucking a penis is very low). In the case of an HIV positive person licking a vagina, the woman being licked has a virtually zero risk of acquiring HIV.
More on Oral Sex at TheBody.com
To find out more about the risk from oral sex, we recommend the following articles:
In addition, our Q&A experts sometimes address questions about oral sex in our "Ask the Experts" forums. Here are some of those questions and our experts' responses:
- Risk of getting infected by licking a vagina
I licked the vagina of a prostitute for about a minute. I am not sure whether vaginal fluid was present or not. I brushed my teeth 30-40 mins after this incident, as after licking her vagina it smelt bad.
- Can fingering and sucking vaginal fluid cause HIV?
She fingered her vagina and put that finger into her mouth and breast. Then I sucked her breast and had a deep kiss. I had some slight damage on my upper lip.