VanGogh, as is often the case with Artists and other creative types, suffered from mental illness and an addiction to Absinthe, also known as "the green fairy," which is now banned in the US,and was quite fond of visiting prostitutes.

Technically he didn't "lose" his ear, he cut off only the lobe of his left ear and gave it, in an envelope, to a prostitute named Rachel at a brothel he frequented, with the instructions to "guard this object carefully".

An accurate diagnosis of Van Gogh's illness is still unavailable, but we do know a few things for sure:

1)he acquired syphillis from the prostitutes he visited and

2)there was a family history of mental illness.

Recently, a new theory has evolved which states something to the effect that he may have had a congenital brain lesion that was exacerbated by his regular ingestion of absinthe.

He was a very odd person. He once urinated in the fireplace of the queens castle for no particular reason.