ATROPINE.

the deadly nightshade plant. 

The nice looking plant shown above is another potential killer. Within this plant a compound commonly called atropine is produced. Cases of atropine poisoning are relatively common and have been fatal. Atropine effects the central nervous system. It acts as a specific muscarinic receptor antagonist, blocking peripheral nerves. One effect of this compound is the induction of psychosis.

Atropine is an example of a plant alkaloid. Poisoning by this substance is easily recognized. A dry mouth quickly develops followed by feelings  of nausea and giddiness. Many people poisoned by atropine have claimed that they could not control their behavior and have done some remarkably strange things. 

One common effect of atropine is pupil dilation. Ancient Egyptian women used plant material containing atropine for its cosmetic effects.