Can You Catch an STI from Oral Sex?

Oral sex is often seen as a “safer” alternative to intercourse, but that doesn’t mean it’s risk-free. Many people are surprised to learn that you can catch sexually transmitted infections (STIs) from oral sex - even if no symptoms appear.

Let’s look at which infections can be passed on this way, the signs to watch for, and how to protect yourself.

How Oral Sex Spreads STIs

STIs are caused by bacteria, viruses, or parasites that live in the genital tract, throat, or mouth. During oral sex, these organisms can be transferred through:

• Contact with genital fluids (semen or vaginal secretions)
• Skin-to-skin contact with sores or infected tissue
• Tiny cuts or abrasions in the mouth or throat

This means infections don’t just spread through penetration, oral sex carries real risks too.

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Which STIs Can You Get from Oral Sex?

Chlamydia

• Can infect the throat (oral chlamydia), though often symptomless.
• May cause sore throat or swollen glands.

Gonorrhoea

• Commonly affects the throat and is sometimes called “oral gonorrhoea.”
• Symptoms may include sore throat or discomfort when swallowing, but many people notice nothing at all.

Syphilis

• Can spread through oral sex if there are sores in the mouth or genital area.
• Early signs include painless ulcers that can go unnoticed.

Herpes (HSV-1 and HSV-2)

• Oral herpes (cold sores) can spread to the genitals.
• Genital herpes can also be passed to the mouth.

HPV (Human Papillomavirus)

• Can be transmitted through oral sex and may increase the risk of throat cancers.

HIV

• Risk is lower than with vaginal or anal sex, but transmission is still possible, especially if there are mouth ulcers or bleeding gums.

Symptoms to Look Out For

Infections from oral sex often cause mild or no symptoms, but possible warning signs include:

• Persistent sore throat
• Redness or irritation in the mouth
• Swollen glands
• Sores, blisters, or ulcers in the mouth or on the lips
• Unusual discharge at the back of the throat

Because symptoms are often absent, testing is the only reliable way to know.

How to Protect Yourself

• Use protection – Condoms and dental dams reduce the risk significantly.
• Avoid oral sex during outbreaks – For example, cold sores or genital sores.
• Get vaccinated – The HPV vaccine protects against the strains most linked to cancer.
• Get tested regularly – Especially if you have new or multiple partners.

👉 Stay safe and informed. Arrange your STI screen at STI Clinic.

Protect Yourself and Your Partner

Early testing and treatment make all the difference. Book your private STI screening now with our expert sexual health team.

Book us online 02071830494

Why Testing Matters

Even though oral sex carries a lower risk than penetrative sex, it’s not risk-free. Because infections like gonorrhoea, chlamydia, and syphilis can thrive in the throat without obvious symptoms, you may never know you’re infected unless you test.

At STI Clinic, our comprehensive packages include throat swabs and blood tests to detect infections that standard checks might miss.

👉 For peace of mind, book your discreet STI test today at STI Clinic.

Final Thoughts

So, can you catch an STI from oral sex? Yes, infections like gonorrhoea, chlamydia, herpes, HPV, syphilis, and even HIV can spread this way. The risk may be lower than with vaginal or anal sex, but it’s not zero.

The safest approach is to combine protection with regular testing. That way, you’ll know your status, protect your partner, and avoid long-term complications.

👉 Take charge of your health. Book a confidential test now with STI Clinic.