The human body produces many things that are toxic if ingested. Top of my head: * Carbon dioxide - albeit just to get rid of, but it does make it :D * Hydroc

The human body produces many things that are toxic if ingested. Top of my head: * Carbon dioxide - albeit just to get rid of, but it does make it :D * Hydrochloric acid * Hydrogen peroxide * Ammonia * Formaldehyde Then of course the human body creates pyrogens to fight off illness, even if they literally cook your sugar creating brain :D