Why do they have nosebleed?

Because Japan is fucking messed up.

there is an history to that they even post it on this site

I remember reading this somewhere, but it's supposed to symbolize a sudden flow of blood to well......another part of the body. I shouldn't really have to explain and please don't make me. T_T

Proble because tthey have nothing better to do and when they see a girl they get way to happy! And I tthink thats whay guys get nosebleeds alot!

Dr.Green:well its quit simple when u see stuff u like u mostly blush riight nd gt all hot nside nd feel wierd but n a goood way lets way men r thermoneters and thers some level of when the heat gets 2 high it explodes and al the ed stuff comes out ich is blood wich is when they bleed wich we call nosebleed so lets say im walkin on street and a girl with a skirt pasess by and a wind pulled the skirt up then i would ofcourse i would blush overload ith thhat good feeling and all that comes out my nose wich is nosebleed

I think its cuz when u blush blood rushes to ur face. Then it comes out of noses.... animes tend to do things over the top so its very explosive ^^

It is because of one of the 46 laws of anime. Law 40. Law of Nasal Sanguination When sexually aroused, males in Anime don't get erections, they get nosebleeds. No one's sure why this is, though... the current theory suggests that larger eyes means smaller sinuses and thinner sinus tissue (see Law #38 above). Females don't get nosebleeds, but invariably get one heck of a blush along the cheeks and across the nose, suggesting a lot of bloodflow to that region.

probably coz dy r guys n guys gt xcited soon n their blood boils and there is no othr way of comin out.. atleast cant show (if u knw wt i mean).. so it flows through nose... and besides animes r meant 2 b funny n creative :P