Wiki page on McCandless: 
 <a href="http://en.wikipedia.org/wiki/Christopher_McCandless" rel="nofollow">http://en.wikipedia.org/wiki/Christopher_McCandless</a>
The speculation is that he died either from eating <a href="http://en.wikipedia.org/wiki/Hedysarum" rel="nofollow">http://en.wikipedia.org/wiki/Hedysarum</a> or Hedysarum with "Black Patch Desease" fungus : <a href="http://en.wikipedia.org/wiki/Rhizoctonia_leguminicola" rel="nofollow">http://en.wikipedia.org/wiki/Rhizoctonia_leguminicola</a><p>I just watched the movie about him "Into The Wild" -- pretty interesting.