How do I reduce or eliminate cortisol from my system?

Consider this previous Yahoo answer that suggests using St. John's Wart.
https://answers.yahoo.com/question/index;_ylt=AwrC1jE6CXJeyU8AWwdPmolQ;_ylu=X3oDMTBybGY3bmpvBGNvbG8DYmYxBHBvcwMyBHZ0aWQDBHNlYwNzcg--?qid=20091129145039AAs3oRt

My brother had a brain tumor, an ependymoma, and the removal of the tumor and the radiation that followed resulted in his body not being able to produce cortisol.  He has to take cortisol pills or he'll die, and if he gets stressed out, he has to take extra or he'll die.  He's constantly monitoring his cortisol to keep from dying because his body produces none.  If he gets put into a highly stressful situation, especially something that triggers his fight or flight response, and doesn't have his cortisol pills to take some immediately, he will fall over and die.  So be careful what you wish for.