text: can diseases be transmitted by oral sex?   various diseases are contagious by oral sexual activity. although full information is available, the diseases listed are some of the ones that can be caught during oral sex. see also the full list of diseases contagious from sex. the oral sexual act also involves close physical contact and transfer of fluids, so see also diseases contagious from physical contact, diseases contagious from bodily fluids, diseases contagious from saliva, diseases contagious from kissing, oral sex, and other types of contagion.   check out the link below for full details