Nature has created poison for the benefit of organisms depending on it and they are beneficial to them as weli as to others in some forms .For instance the venom of snake protects it from enemies but is beneficial in some doses for treatment of diseases , many plants have poisons that are good medicines. poisons are created for good but when misused become fatal for both producer and user. Likewise poisons in human society can also make one think of leading a secular life by avoiding such poisons

The opposite is also true as well...medicines can be used as poisons.....the 2 most famous ones being: Warfarin (or Coumadin) an anti-coagulant being used as a rat poison (it was actually used as a rat poison before it was used to treat human coagulation disorders) and Foxglove giving rise to Digitalis (Digoxin) to regulate the heart rate but is fatal in it's pure form