Most sexually transmitted infections can be passed on through unprotected oral sex.
Some, like gonorrhoea, genital herpes, genital warts, chlamydia and syphilis are easily caught through unprotected oral sex with a man or a woman. Though the risk is lower, HIV can also be passed on from a man during oral sex if his semen enters the bloodstream. This can happen if there are small cuts or sores in the mouth of the person giving him oral sex.
A woman’s vaginal fluid can also contain the HIV virus and can pass into the bloodstream through cuts in the mouth.
Find out more about sexually transmitted infections (STIs)