My boys are fine. I'm just interested to know what are the main causes of a male dog leaking blood through his penis? The reason I ask is, my old boy Tyson had to PTS 6 years ago due to this and two other problems that were discovered. He was castrated as a result of the leaking blood but it made no difference. The vets never really gave me an answer other than he definitely had cancer someone in his body, he was going blind and there was something wrong with his brain, after extensive testing. Does anyone know the main causes of this?