I've heard about people dying from being "intoxicated" (I'm not sure if thats the term) from smelling their own farts.
There is a story of a man that actually died:
A terrible diet and room with no ventilation are being blamed for the death of a man who was killed by his own gas. There was no mark on his body but an autopsy showed large amounts of methane gas in his system. His diet had consisted primarily of beans and cabbage (and a couple of other things). It was just the right combination of foods. It appears that the man died in his sleep from breathing the poisonous cloud that was hanging over his bed. Had he been outside or had his windows been opened, it wouldn't have been fatal, but the man was shut up in his near airtight bedroom. According to the article, "He was a big man with a huge capacity for creating 'this deadly gas.'" Three of the rescuers got sick and one was hospitalized.
Can your own farts kill you?