Brushing your teeth, using dental floss and visiting the dentist regularly are an entirely natural part of many people’s health routines. But what role does our oral health actually play in sex? That is a question we rarely think about in everyday life. Yet oral health and sexual health are more closely connected than many people realise.
During oral sex, the lips, tongue and oral mucosa come into contact with the genital area. Sexually transmitted infections, known as STIs, can also be passed on in this way. But what does this mean for our oral health? Which infections can be transmitted from the genital area to the mouth and throat during oral sex, and vice versa? What role do bleeding gums or small injuries play? And is it actually advisable to brush your teeth immediately before oral sex?
Together with dentist Maximilian Fiesel, we explore these and other questions. We examine the connections between oral sex, oral health and sexually transmitted infections, address common uncertainties and explain how taking a conscious approach to oral health can also contribute to a self-determined and responsible approach to sexuality.
How Can Infections Be Transmitted During Oral Sex?
Sexually transmitted infections do not affect only the genital area. During oral sex, certain pathogens can be transmitted from the genital or anal area to the mouth and throat. The reverse is also possible: infections in the mouth and throat can be passed to another person’s genital area during oral sex. The way transmission occurs depends on the specific pathogen. While some infections can be transmitted through direct skin or mucosal contact, infectious bodily fluids also play a role in others. It is important to know that ejaculation is not necessary for an STI to be transmitted.
Infections that can be transmitted during oral sex include gonorrhoea, chlamydia, syphilis, herpes, HPV and HIV. They differ in their transmission routes, possible symptoms, health consequences and respective transmission risks. HIV, in particular, requires a differentiated assessment, as the risk of transmission during oral sex is extremely low compared with vaginal or anal sex.
Gonorrhoea can affect the throat as well as the genital area. One particularly concerning aspect is that a throat infection frequently causes no noticeable symptoms. As a result, people may not even realise they are infected and may unknowingly transmit the pathogen during subsequent sexual contact. *2
Chlamydia can also be transmitted during oral sex and infect the throat. Compared with infections in the genital area, throat infections with chlamydia are less common and usually remain asymptomatic. The significance of these infections for further transmission has not yet been conclusively established by scientific research. *2
Syphilis is primarily transmitted through direct contact with infectious skin or mucosal lesions. An infection may become noticeable, for example, through an initially mostly painless sore on the lips or inside the mouth. As this sore often causes no discomfort and may heal even without treatment, it can go unnoticed. However, this does not mean that the infection has disappeared. If left untreated, syphilis can progress and cause serious health consequences. Early diagnosis and medical treatment are therefore particularly important.
HIV can, in principle, also be transmitted during oral sex. However, the transmission risk is considered extremely low and is significantly lower than the risk associated with unprotected vaginal or anal sex. Saliva alone does not transmit HIV. A theoretically increased risk may exist if bodily fluids containing HIV come into contact with open wounds or damaged mucous membranes. However, the extent to which such factors actually influence the already extremely low transmission risk during oral sex cannot be reliably quantified by scientific research. It is important to know that people living with HIV who maintain an undetectable viral load through effective treatment do not transmit the virus sexually (U=U: Undetectable = Untransmittable). *1
Which Infections Can Easily Be Underestimated During Oral Sex?
Not every sexually transmitted infection causes noticeable symptoms. During oral sex, it is therefore often underestimated that infections may be present and transmitted even when no symptoms occur.
This applies, for example, to gonorrhoea and chlamydia in the throat, as well as infections such as herpes and HPV. While some pathogens can remain undetected for extended periods, others cause only temporary symptoms. The key point is that an apparently normal appearance does not automatically mean that no infection is present or that transmission can be ruled out.
Why the Risks Cannot Be Compared in General Terms
Oral sex is often considered inherently lower risk than other sexual practices. However, this assessment is too simplistic, as the risk of transmission varies considerably depending on the pathogen. While the risk of contracting HIV during oral sex is extremely low, other sexually transmitted infections, such as gonorrhoea or herpes, can also be transmitted through this sexual practice. *1
Herpes, for example, can be transmitted through direct contact with infected skin or mucous membranes. Syphilis is transmitted through contact with infectious lesions, while an unnoticed throat infection can also play a role in the transmission of gonorrhoea. The individual risk therefore depends not only on the specific pathogen but also on the type of sexual contact.
“Understanding the different transmission routes of sexually transmitted infections is crucial. Not every infection is transmitted in the same way, and not every sexual practice carries the same risks. Understanding these connections allows people to assess potential risks more realistically and make informed decisions about which protective measures are appropriate,” explains dentist Maximilian Fiesel.
Oral-anal contact, known as anilingus, introduces additional transmission routes. These can include hepatitis A and certain intestinal pathogens. This is another reason why it is important to consider which parts of the body come into contact when assessing potential infection risks.
Herpes: When the Lips and Genital Area Come into Contact
Oral herpes and genital herpes are often perceived as two separate infections. In fact, herpes simplex virus type 1 (HSV-1), which frequently causes oral herpes, can also be transmitted to the genital area during oral sex. Genital herpes is therefore not caused exclusively by HSV-2. Conversely, herpes viruses can also be transmitted from the genital area to the mouth.
Visible herpes blisters are a clear sign that oral sex should be avoided temporarily. However, tingling, burning or a feeling of tightness may already indicate the beginning of an outbreak. Direct contact with the affected areas should therefore be avoided from the first signs until the lesions have completely healed.
It is important to know that herpes can also be transmitted without visible blisters. This is because herpes viruses can sometimes be shed through the skin or mucous membranes even when no noticeable symptoms are present. This does not mean that every contact automatically leads to infection. However, it explains why the absence of visible symptoms does not provide complete protection. If symptoms recur or there are questions about individual transmission risks, seeking medical advice may be helpful. *3
HPV: The Mouth and Throat Can Also Be Affected
Human papillomaviruses, commonly known as HPV, can infect the skin and mucous membranes. In addition to the genital area, certain types can also affect the mouth and throat. Transmission is possible during oral sex, among other forms of contact. Many people do not notice an HPV infection because it frequently causes no recognisable symptoms. In most cases, the immune system controls the infection within one to two years, after which it is no longer detectable. *4
Not all HPV types have the same consequences. Some can cause benign warts, while others are classified as high-risk types. If an infection with certain high-risk types persists over an extended period, it can contribute to the development of certain cancers in the mouth and throat. The tonsils and base of the tongue are particularly affected. *4
The significance of this connection received greater public attention in 2013 through Hollywood star Michael Douglas. *6 The actor, who was diagnosed with cancer in the mouth and throat area in 2010, discussed the connection between HPV, oral sex and certain cancers in an interview. His comments made headlines around the world and drew attention to a health issue that had previously received relatively little public attention. An important distinction must be made here: although the connection between certain HPV types and cancers of the mouth and throat is scientifically established, the original route of transmission of an individual HPV infection generally cannot be determined with certainty.
However, an HPV infection is by no means equivalent to cancer. The vast majority of infections resolve without consequences or become undetectable after some time. Factors influencing the risk of disease include the virus type and whether the infection persists over an extended period.
HPV vaccination is therefore an important part of prevention. It protects against certain HPV types, including those associated with cancer. In Germany, the Standing Committee on Vaccination (STIKO) recommends vaccination for girls and boys aged 9 to 14. Missed vaccinations should be made up by the age of 17, inclusive. The greatest benefit is achieved when vaccination takes place before the first sexual contacts. Adults may also benefit from vaccination in individual cases and can discuss the potential benefits with a healthcare professional. The vaccine does not treat an existing infection and does not protect against all HPV types or other sexually transmitted infections. *4
Recognising Changes in the Mouth and Assessing Them Correctly
Blisters, open sores, unusual changes in the oral mucosa or persistent discomfort may warrant a medical examination. Syphilis, for example, can cause painless ulcers, while herpes often manifests as painful blisters and sores. However, the cause cannot be reliably determined based on appearance alone.
Not every change in the mouth automatically indicates a sexually transmitted infection. Canker sores, for example, are common mucosal ulcers that are generally not contagious. Small injuries, such as those caused by accidentally biting the inside of the cheek or by a sharp edge of a tooth, can also cause sore areas. Even if an unusual finding appears after oral sex, this does not necessarily mean that it is related to an STI.
It is therefore all the more important to discuss changes openly and have potential causes medically assessed. Dentist Maximilian Fiesel emphasises: “An unusual change in the mouth can have various causes. A possible connection with oral sex is relevant medical information that can help identify the underlying cause. No one should feel the need to justify asking their dentist about such concerns, let alone feel ashamed of doing so.”
During a dental examination, changes affecting the teeth, gums and visible oral mucosa can be identified, and further examinations can be recommended if necessary. However, a reliable STI diagnosis requires targeted testing, depending on the suspected infection. It is also important to remember that an infection cannot be ruled out simply because no abnormalities are found during a dental examination. Gonorrhoea and chlamydia, in particular, can affect the throat without causing noticeable symptoms. *2
Unusual, worsening or recurring changes should therefore be medically assessed. This is particularly important for sores that do not heal within two to three weeks. If an STI is suspected or a sexual partner has been diagnosed with an infection, seeking medical advice is advisable even in the absence of visible symptoms.
The Role of the Gums and Oral Mucosa
Healthy gums and intact oral mucosa form a natural protective barrier against external influences and pathogens. Inflammation, bleeding gums or open sores can compromise this barrier and create additional entry points for certain infections. However, the extent to which bleeding gums actually increase the risk of STI transmission during oral sex cannot be reliably quantified by scientific research. It is also important to remember that certain STIs can be transmitted even through intact oral mucosa. *1
If the gums are actively bleeding, there are open wounds, painful canker sores or acute inflammation, it is therefore advisable to temporarily avoid oral sex until the affected areas have healed. This also applies after dental procedures while wounds remain or the dental practice recommends avoiding strain on the affected area. Anyone who regularly experiences bleeding gums should have the cause assessed by a dentist. Unusual changes in another person’s mouth or genital area are also a good reason to avoid direct contact initially and seek medical advice if necessary.
Oral Care Before and After Oral Sex
Good oral hygiene is important for healthy teeth and gums. However, brushing your teeth particularly thoroughly or using dental floss immediately before oral sex is not necessarily advisable. These activities can cause small injuries or bleeding, especially if the gums are sensitive or inflamed. The Oral Health Foundation therefore recommends avoiding brushing and flossing immediately before and after oral sex. However, this does not establish a scientifically confirmed minimum time interval. *5
“During oral sex, the oral mucosa comes into direct contact with another person’s skin, mucous membranes and bodily fluids. If the gums have just been irritated by vigorous brushing or flossing, or are bleeding, the natural protective barrier may be compromised. I therefore recommend not scheduling oral hygiene immediately before oral sex and allowing the gums sufficient time to recover if they are irritated,” explains dentist Maximilian Fiesel.
No special cleaning routine is required after oral sex either. Anyone who wishes to do so can gently rinse their mouth with water. It is important to know that neither brushing your teeth nor using mouthwash can reverse STI transmission that may already have occurred. Good oral hygiene contributes to overall oral health but does not replace appropriate protective measures during oral sex.
Making Oral Sex More Conscious and Safer
Condoms and dental dams can reduce the risk of STI transmission during oral sex. Condoms are used during oral sex involving the penis, while dental dams, also known as oral barriers, provide a protective barrier during oral contact with the vulva or anus. These thin sheets are placed between the mouth and the body, preventing direct contact with the covered areas of skin and mucous membranes as well as the corresponding bodily fluids. *1
Correct use is important: a dental dam should be placed before the first contact, held in position throughout oral sex and used only once. It should also not be turned over during use. Condoms must likewise be changed for every new sexual act. Anyone using lubricant should ensure that it is compatible with the material in question.
However, condoms and dental dams do not provide complete protection against all STIs. Infections such as herpes, HPV and syphilis can also be transmitted through areas of skin and mucous membranes that are not covered by the barrier. It is therefore advisable to combine different preventive measures: appropriate protective methods, recommended vaccinations, STI testing and medical assessment of possible symptoms. Open communication about sexual health, protection and personal boundaries is equally important. Informed decisions and mutual trust are essential foundations for a conscious and self-determined approach to sexuality.
Why Oral Sex Should Also Be Discussed During STI Testing
Sexually transmitted infections do not always cause noticeable symptoms. STI testing can therefore be an important part of sexual healthcare. Which tests are appropriate and how frequently testing should take place depends on the individual situation, for example, new or changing sexual partners, the types of sexual activity involved or known infections in partners. There is no single testing schedule that is suitable for everyone. A medical consultation or a specialised counselling service can help determine which tests are appropriate.
It is important to discuss oral sex openly as well. Not every STI test automatically detects infections in the mouth and throat. For example, a targeted throat swab may be necessary to detect gonorrhoea or chlamydia in the throat. A urine test or a swab taken from the genital area does not automatically examine this part of the body. Blood tests cannot detect every STI either. The appropriate testing method therefore depends on both the suspected pathogen and the affected area of the body. *2
The timing of the test is also crucial, alongside choosing the right testing method. Some pathogens cannot be reliably detected immediately after a possible exposure. Medical advice should therefore be sought on when testing is appropriate and whether a repeat test may be necessary at a later stage. If an STI is diagnosed, appropriate treatment and, where necessary, informing affected sexual partners are important next steps.
Oral Health as Part of Sexual Health
Sexual health encompasses far more than the genital area. Our oral health also plays a role and deserves attention. Understanding the connections, assessing potential risks realistically and taking a conscious approach to personal health provide an important foundation for making informed decisions about sexuality. The collaboration with dentist Maximilian Fiesel demonstrates how important it is to approach sexual health from different perspectives and address topics that often receive too little attention in everyday life. This also includes being able to ask questions about oral sex openly during dental appointments or medical consultations, without feeling uncertain or ashamed.
Knowledge, open communication and a conscious approach to our own bodies not only contribute to our health but also enable a more natural and self-determined approach to intimacy and sexuality.
FAQ
Which STIs Can Affect the Mouth and Throat During Oral Sex?
These include gonorrhoea, chlamydia, syphilis, herpes and HPV, among others. Transmission routes and potential consequences vary depending on the pathogen. During oral-anal contact, hepatitis A and intestinal pathogens can also be transmitted.
Can an STI in the Throat Occur Without Symptoms?
Yes. Gonorrhoea and chlamydia in the throat, in particular, can be present without causing symptoms. An apparently healthy mouth or the absence of a sore throat therefore does not rule out an infection.
Can Oral Herpes Cause Genital Herpes During Oral Sex?
Yes. HSV-1 can be transmitted from the mouth to the genital area. This can also happen without visible blisters. Direct contact with the affected area should be avoided at the first signs of an outbreak and until the area has completely healed.
Are Canker Sores a Sign of an STI?
Not necessarily. Typical canker sores are not contagious and often have other causes. Nevertheless, unusual or persistent sores should be examined, particularly if they do not heal within two to three weeks.
Should You Brush Your Teeth Immediately Before Oral Sex?
Regular oral care is beneficial, but brushing and flossing immediately beforehand can cause small injuries or bleeding. They do not prevent STI transmission. If desired, the mouth can be gently rinsed with water.
About Dentist Maximilian Fiesel
Maximilian Fiesel is a dentist and Managing Director of Zahnhaus Fiesel MVZ GmbH. His areas of treatment include caring for patients with dental anxiety, implantology, aligner treatments and aesthetic dentistry.
Together with pjur, he advocates open and evidence-based education at the intersection of oral health and sexual health. He contributes his dental expertise to explain medical connections in an accessible way, reduce uncertainty and raise awareness of the importance of oral health beyond conventional dental care. His aim is to make knowledge accessible, encourage open discussion of sensitive health topics and empower people to address subjects that are often considered taboo as a natural part of everyday conversation.
Links
Instagram: @zahndoc.max
Dental Practice Website, Monheim, Germany: Zahnhaus Monheim – Your Dental Practice in Monheim
Sources
*1 CDC: About STI Risk and Oral Sex. Transmission routes, differences in risk and prevention.
https://www.cdc.gov/sti/about/about-sti-risk-and-oral-sex.html
*2 CDC: Sexually Transmitted Infections Treatment Guidelines (2021). Medical information on gonorrhoea, chlamydia, syphilis and pharyngeal diagnostics:
https://www.cdc.gov/std/treatment-guidelines/gonorrhea-adults.htm | https://www.cdc.gov/std/treatment-guidelines/chlamydia.htm | https://www.cdc.gov/std/treatment-guidelines/syphilis.htm
*3 WHO: Herpes simplex virus. Transmission and asymptomatic infections.
https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus
*4 Robert Koch Institute: Frequently Asked Questions About HPV Vaccination and HPV Infection. HPV, possible complications and vaccination recommendations.
https://www.rki.de/SharedDocs/FAQs/DE/Impfen/HPV/FAQ-Liste_HPV_Impfen.html?nn=16777040
*5 Oral Health Foundation: Oral Sex and Oral Health – What You Need to Know. Advice on oral care before and after oral sex.
https://www.dentalhealth.org/blog/oral-sex-and-oral-health
*6 The Guardian: “Michael Douglas: Oral Sex Caused My Cancer”, 2 June 2013.
https://www.theguardian.com/film/2013/jun/02/michael-douglas-oral-sex-cancer
Medical Disclaimer
The content of this article is intended solely for general information and educational purposes. It has been prepared with the utmost care but does not replace individual medical advice, examination or diagnosis. If you experience health problems, have questions about sexually transmitted infections or are concerned about a possible risk of infection, you should seek medical advice. Medical knowledge and recommendations may change over time.