St. Pierre revealed why he ended his career

"‎The reason I actually retired is because I started developing a condition called ileocolitis. It's an inflammation of the intestines, and before the Bisping fight I had trouble gaining weight. I had to force myself to eat, and that's probably what caused me to get ileocolitis. When I was diagnosed with it, I started fasting periodically to get rid of it, and it helped. I don't have to take medication anymore. But then it was that after I went to the bathroom, there was a lot of blood. I thought I had cancer," MMA Mania quoted St-Pierre as saying.