Here's some STD's transmissible through kissing, there may be more but these are the first ones I found.
*Herpes virus Symplex I and II - only contagious during a breakout, but sometimes there are no visible symptoms during a breakout, here's a little fun fact for all the high-and-mighties out there who think onle "dirty" people can have/give an std, over 80% of Americans are infected with HSV-I, AKA cold sores or fever blisters, it is a virus, it never goes away even if you never show any visible signs after the initial outbreak you still carry the disease and can pass it on
*Hepatitis - spread through sharing body fluids including saliva
*Syphilis - it is treatable, but there are sometimes no symptoms so the carrier may not know they are infected
*HIV (only if the person has an open sore in their mouth)
I got this information off of a Planned Parenthhod site, the link is below, I'm sure you could find more if you did a more in-depth search.
http://www.ppnyc.org/facts/facts/stds.html
you can also go to the parent site http://www.plannedparenthood.org/pp2/portal/
Comments made by sweetdreams