Some key facts are:
Dams act as a barrier during oral sex involving contact between the mouth and the vulva, or mouth and the anus.
The STIs most commonly passed on through oral sex are: gonorrhoea, genital herpes and syphilis. Infections which can still be transmitted through oral sex (although less frequently) are: chlamydia, HIV, hepatitis A, hepatitis B and hepatitis C, genital warts, and pubic lice.
Each dental dam should only be used once, and you should use a new dam for each sexual activity – for example you shouldn’t move a dam from the anus to the vulva as this can transmit bacteria and cause an infection.
Lubricant can also be used with dams. A small amount can be put on the side in contact with the vulva or anus. Be careful not to use oil-based lubricants with latex dental dams as these will rot the latex and prevent the dam from working. It is better to stick to water based lubricants.
You can get dental dams at:
You can also make your own dams from condoms, by rolling the condom out, cutting off the tip and the ring, and then along its length to create a rectangle.
Contraception and sexual health services such as Brook are free and confidential, including for people under the age of 16. Health professionals work to strict guidelines and won’t tell anyone else about your visit unless they believe you're at serious risk of immediate harm. Find out more about Brook’s confidentiality policy.
If anything goes wrong or you are worried you may need to be tested for STIs.
Page reviewed: September 2015
Next review due: September 2017