Oral Sex & STI Transmission

Going from first base to second base? Just before you do that, you might want to make sure it’s absolutely safe! 

Oral sex is the stimulation of the genitals using the mouth and tongue. It is one of the ways that sexually transmitted infections (STIs) are most frequently passed on. Oral sex involves using the mouth, lips, or tongue to stimulate the penis (fellatio), vagina (cunnilingus), or anus (anilingus) of a sex partner.

Is Oral Sex Safer than Vaginal or Anal Sex?

Many STDs can be spread through oral sex. However, it is difficult to compare the exact risks of getting specific STDs from specific types of sexual activity. This is mostly because most people who have oral sex also have vaginal or anal sex. Also, limited studies have looked at the risks of getting STDs other than HIV from giving oral sex on the vagina or anus, compared to giving oral sex on the penis.

From what the studies have shown, the risk of getting HIV from having oral sex with an infected partner (either giving or getting oral sex) is much lower than the risk of getting HIV from anal or vaginal sex with an infected partner. This may not be true for other STDs intact few studies showed that 1 out of 5 gay men that has acquired syphilis reported having only oral sex.

Getting HIV from oral sex may be extremely low, but it is hard to know the exact risk. It doesn’t matter if you are having oral sex, you should still protect yourself. Repeated unprotected oral sex exposure to HIV may represent a considerable risk for spread of other STDs. 


It is possible that getting certain other STDs, such as chlamydia or gonorrhea, in the throat may not pose as great a threat to an infected person’s health as getting an STD in the genital area or rectum but having such infections in the throat might increase the risk of getting HIV. Having gonorrhea in the throat also may lead to spread of the disease throughout the body. 

In addition having infections of chlamydia and gonorrhea in the throat may make it easier to spread these infections to others through oral sex. This is especially important for gonorrhea, since throat infections can be harder to treat than urinary, genital or rectal infections.

Infections from certain STDs, such as syphilis and HIV, spread throughout the body. Therefore, infections that are acquired in the throat may lead to the same health problems as infections acquired in the genitals or rectum.

Mouth and throat infections by certain types of HPV may develop into oral or neck cancer.

Also read: What you need to know about STDs

What may increase the chances of giving or getting an STD through Oral Sex?

It is possible that certain factors may increase a person’s chances of getting HIV or other STDs during oral sex if exposed to an infected partner, such as:

  • Having poor oral health which can include tooth decay, gum disease or bleeding gums, and oral cancer.
  • Having sores in the mouth or on the genitals.
  • Being exposed to the “pre-cum” or “cum” (also known as pre-ejaculate or ejaculate) of an infected partner.

What Can You Do to Prevent STD Transmission During Oral Sex?

You can lower your chances of giving or getting STDs during oral sex by using a condom, dental dam or other barrier method every time you have oral sex.

For oral sex on the penis:

  • Cover the penis with a non-lubricated latex condom.
  • Use plastic (polyurethane) condoms if you or your partner is allergic to latex.

For oral sex on the vagina or anus:

  • Use a dental dam.
  • Cut open a condom to make a square, and put it between the mouth and the partner’s vagina or anus.

The only way to avoid STDs is to not have vaginal, anal, or oral sex, which yes, its not possible and it does sound silly! 

If you are sexually active, you can do the following things to lower your chances of getting an STD:

  • Being in a long-term mutually monogamous relationship with a partner who is not infected with an STD (e.g., a partner who has been tested and has negative STD test results).
  • Using latex condoms the right way every time you have sex.

It’s important to remember that many infected individuals may be unaware of their infection because STDs often have no symptoms and are unrecognized. Most sexually transmitted infections are easily treated but treatment should be started as soon as possible. Some infections, such as HIV, never leave the body and cannot be cured. There are drugs available that can reduce the symptoms and help prevent or delay the development of late stage HIV infection.

If left untreated, many sexually transmitted infections can be painful or uncomfortable, can permanently damage your health and fertility, and can be passed on to a partner.




The exact risk of infection is not known. If he has an infection that can be passed on through semen or blood (which can be present in semen) you are probably at more risk if he ejaculates in your mouth. The risk is probably the same whether you swallow the semen or spit it out. The more time his penis and/or semen is in your mouth, the greater the risk. Infections passed on through semen include chlamydia, gonorrhoea, hepatitis and HIV.

Pre-ejaculatory fluid (pre-cum) can also carry infection, so you could be at risk if a partner’s pre-cum gets in your mouth, even if he doesn’t ejaculate in your mouth.



If a woman has an infection that can be passed on through blood there will be a higher risk if you give her oral sex when she has her period. The infection will be more likely to pass to you if you have any sores, cuts, ulcers or inflammation in or around your mouth.

Infections passed on through blood include hepatitis B, hepatitis C and HIV.



If a partner is HIV positive and ejaculates in your mouth, you have a small risk of getting HIV. The risk depends on how much active HIV infection is in his bloodstream. It also depends on whether you have any cuts, sores or ulcers in your mouth or on your lips.

If you are worried after having sexual contact with an HIV positive partner, you can visit us. We will assess your situation to see whether taking anti-HIV drugs, known as Post Exposure Prophylaxis (PEP), would be helpful for you. PEP is more effective the sooner it is used. The latest it can be given is 72 hours after the oral sex happened.



Although it is possible to detect HIV in urine and saliva, the level of virus in these fluids is thought to be too low to be infectious. In addition, saliva contains protective substances which reduce the likelihood of the virus being passed on. But if the saliva has blood in it, from cuts in the mouth for example, or from unhealed piercings, then this can make infection possible.

Gums sometimes bleed after you brush your teeth, so try to avoid brushing or flossing your teeth immediately before or after oral sex.

Next read: STD Window Period & Incubation period: When To Get STD Test

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