Oral Sex: STI and HIV Risks Explained

Q: Oral sex, risk-free?

That's what many people think. For HIV, the risk is indeed low. But for other STIs, oral sex is one of the main transmission routes between men. Sexosafe (Santé publique France) sums it up: the smallest micro-tear in the mouth can be enough to pass on an STI.

Q: What about HIV?

The risk mainly exists with ejaculation in the mouth (or lots of pre-cum, deep throat that irritates the throat) with an untreated HIV-positive partner. Sexosafe says oral sex with ejaculation, with a partner whose viral load is above 1,000 copies/mL, warrants seeking [PEP](/en/pep-definition-hiv-french-gay-vocabulary/). With an undetectable partner or if you're on PrEP, there's no HIV risk.

Q: Which STIs pass through oral sex?

According to Sexosafe and WHO: throat gonorrhoea and chlamydia, often symptom-free, sometimes a sore throat; and the other way, an infected throat infects the urethra of the guy being sucked; syphilis: a chancre in the mouth or on the penis easily goes unnoticed; herpes: a cold sore can cause genital herpes (HSV-1 is increasingly genital according to WHO); HPV, linked to throat cancers; hepatitis A if oral sex follows anal contact.

Oral sex: what STI and HIV risks, and which precautions?

Definition : Oral sex carries little HIV risk, but it is one of the main routes for gonorrhoea, chlamydia, syphilis, herpes and HPV, often with no symptoms at all in the throat.

Keywords

oral sex, blowjob, sucking, deep throat, cum in mouth, throat STI

Topics

Sexual Health & Prevention

Updated

2026-09-28

Written and reviewed by Frank Reverter · Checked on 2026-09-28 · 4 sources

Oral sex, risk-free?

That’s what many people think. For HIV, the risk is indeed low. But for other STIs, oral sex is one of the main transmission routes between men. Sexosafe (Santé publique France) sums it up: the smallest micro-tear in the mouth can be enough to pass on an STI.

What about HIV?

The risk mainly exists with ejaculation in the mouth (or lots of pre-cum, deep throat that irritates the throat) with an untreated HIV-positive partner. Sexosafe says oral sex with ejaculation, with a partner whose viral load is above 1,000 copies/mL, warrants seeking PEP. With an undetectable partner or if you’re on PrEP, there’s no HIV risk.

Which STIs pass through oral sex?

According to Sexosafe and WHO:

throat gonorrhoea and chlamydia, often symptom-free, sometimes a sore throat; and the other way, an infected throat infects the urethra of the guy being sucked;
syphilis: a chancre in the mouth or on the penis easily goes unnoticed;
herpes: a cold sore can cause genital herpes (HSV-1 is increasingly genital according to WHO);
HPV, linked to throat cancers;
hepatitis A if oral sex follows anal contact.

Precautions that work

Sexosafe recommends:

Don’t brush or floss right before: it creates micro-tears.
No oral sex if you have a sore throat, mouth ulcers, bleeding gums or a cold sore.
Consent for deep throat or rough oral: ask first.
A condom (flavoured if you like) if you want to cut STI risk sharply.
Avoid ejaculation in the mouth with partners whose status you don’t know, if you’re not on PrEP.

The crucial point: throat testing

Most STIs caught through oral sex are symptom-free. Sexosafe insists that testing must include a throat swab (as well as anal and urine swabs and a blood test for syphilis). Every 3 months if you have several partners. If a result is positive, tell your partners.