There are many ways to seriously disrupt our biological machine. Carbon monoxide binds to hemoglobin and prevents oxygen from getting to our cells. Cyanide shuts down the production of ATP in mitochondria. Hemlock is a weed that contains a mixture of at least eight rather toxic molecules that target the nervous system. Thallium ions (Tl+) are particularly toxic because they are highly water soluble and once in the body they bind to ion channels and disrupt other processes that normally function with potassium ions (K+).