How Safe Is Oral Sex?

Readers of a certain age will recall having learned in the mid-1990s, thanks to U.S. President Bill “I Did Not Have Sex with That Woman” Clinton, that oral sex was not sex. Beyond semantic quibbling, this perception has been documented among adolescents and young adults (Tanne, 2005). More to the point, the same population views oral sex as safe sex.

But how “safe” is oral sex? To mark STD Awareness Month, in this article I examine the state of knowledge concerning oral sex and sexually transmitted diseases (STDs), considering both bacterial and viral STDs as well as HIV. In general, the evidence is clear that unprotected oral sex (particularly for the partner who is performing fellatio [giving a blow job to a male] or cunnilingus [performing oral sex on a female]) is not safe and incurs a risk of bacterial or viral STDs. Infection can occur even without ejaculation by an infected male. (Just because he doesn’t “cum” in your mouth, doesn’t protect you.) In addition, symptoms and health effects of STDs may differ for males and females.

Many bacteria and viruses thrive in warm, moist places, and few places provide as ideal a growth medium as the vagina and urethra and the mouth and throat. The fact that their tissue consists of mucous membranes, which are more porous than the skin on the surface of the body, can also make them portals for infectious microbes.

Oral Sex & Bacterial STDs

The chief bacterial STDs include those associated with syphilis, gonorrhea, and chlamydia, which can be tested with blood tests or swabs and treated with antibiotics. Left untreated these bacterial STDs can cause serious, even permanent, health complications. Gonorrhea and chlamydia are quite common, as well as often being asymptomatic.

Centers for Disease Control, Syphilis Fact Sheet

Centers for Disease Control, Gonorrhea Fact Sheet

Centers for Disease Control, Chlamydia Fact Sheet

Oral Sex & Viral STDs

Viral infections by oral sex can include herpes, hepatitis, and human papillomavirus (HPV). Herpes is often asymptomatic and does not usually entail serious health complications, but it comes with associated stigma and shame as a result of its appearance in oral or genital sores. Viral hepatitis is a leading cause of liver cancer, with several distinct forms of the virus. HAV is less likely to be transmitted by oral sex unless one is engaging in oral-anal contact (i.e., “rimming”). HBV is found in blood and in lesser concentrations in body fluids like semen and vaginal secretions; fortunately a vaccine exists to prevent infection, which sexually active people should receive. HCV is less likely to be sexually transmitted. While HPV is commonly associated with cervical cancer in women, males can also be infected. Performing oral sex on an infected person puts one at risk for oropharyngeal (mouth and throat) cancer.

Centers for Disease Control, Herpes Fact Sheet

Centers for Disease Control, Hepatitis B Information

Centers for Disease Control, HPV Information

Oral Sex & HIV

Unprotected anal sex is a well established route of HIV infection, but what about oral sex? Theoretically, performing oral sex on an HIV-infected person is a less-safe but not necessarily unsafe practice. Unless there are tears or sores, the mouth and throat are not hospitable to HIV, which typically needs direct access to the bloodstream. According to the CDC, “Receiving fellatio, giving or receiving cunnilingus, and giving or receiving anilingus carry little to no risk. The highest oral sex risk is to individuals performing fellatio on an HIV-infected man, with ejaculation.” However, a literature search conducted for me by Valori Banfi, nursing librarian at the University of Connecticut, in 2013 suggests a much more complex landscape in which research findings are ambiguous:

The risk of HIV transmission from an infected partner through oral sex is much less than the risk of HIV transmission from anal or vaginal sex. Measuring the exact risk of HIV transmission as a result of oral sex is very difficult. Additionally, because most sexually active individuals practice oral sex in addition to other forms of sex, such as vaginal and/or anal sex, when transmission occurs, it is difficult to determine whether or not it occurred as a result of oral sex or other more risky sexual activities. Finally, several co-factors may increase the risk of HIV transmission through oral sex, including: oral ulcers, bleeding gums, genital sores, and the presence of other STDs. What is known is that HIV has been transmitted through fellatio, cunnilingus, and anilingus. (CDC, 2013)

Centers for Disease Control, HIV & Oral Sex


Performing oral sex entails risks whose calculation becomes complicated when you don’t know the health status of your partner. It is also often the case that partners themselves don’t know their own health status since many STDs are asymptomatic. Some risks may be managed by pharmaceuticals after infection, but many, particularly viral infections, cannot.

If you enjoy casual or anonymous oral sex with multiple partners over time, consider safer-sex, using condoms or dental dams for oral sex, and other risk reduction practices (e.g., mutual masturbation in lieu of oral sex).

Get tested for STDs regularly, either through your regular primary care provider or a public clinic, like those provided by Planned Parenthood.


Centers for Disease Control and Prevention (CDC). 2013. Oral sex and HIV risk.” Retrieved from

Tanne, J. H. (2005). US teenagers think oral sex isn’t real sex. British Medical Journal, 330(7496), 865. Retrieved from

About Thomas Lawrence Long

Associate professor-in-residence, School of Nursing, University of Connecticut; editor and writing coach
This entry was posted in LGBT Health. Bookmark the permalink.

3 Responses to How Safe Is Oral Sex?

  1. waritch says:

    Thanks, Peggy! 8)

    Two quick comments:

    1) a recent MMWR (from March, I believe) contained a case that they are pretty sure represents woman-to-woman transmission of HIV, which is not something that many WSW consider a risk.

    2) your piece mentions condom use near the end as a preventive measure but don’t forget dental dams — they are even available latex-free for folks with a latex allergy or sensitivity.

    Wendy Ritch
    Rutgers (formerly UMDNJ) School of Nursing

    • Thomas Lawrence Long says:

      Thanks, Wendy, for that comment. I’ve updated the article to “give a dam.” I decided not to include that recently reported woman-to-woman HIV case because it seemed in several respects an anomaly and it was not directly related to the exclusive focus (oral sex) of this article. In that report, the fact that the women were using sex toys vigorously during menstrual periods is more likely to have provided the opportunity for infection.

  2. Pingback: Bad Blood? | Lavender Health – LGBTQ Resource Center

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