One man's poison, another man's medicine?

Poisonous plants and animals are widespread in nature and have been used for a great variety of purposes. Brief discussions of a number of examples: aconite, ergot, Euphorbiaceae/Thymelaeaceae, curare, cardiac glycosides, triterpenoid saponins and animal toxins, make the point that, in addition to allowing their use as medicinal agents, the study of such substances has opened up new areas of (bio)chemistry, physiology and pharmacology. But even though the compounds concerned have a relatively low molecular weight, in some cases their examination had to wait until appropriate methods of investigation became available. Understanding the modes of action has allowed the molecules to be used as starting points for the development of useful medicinal agents, a better appreciation of structure-activity relationships having led to improvements in the properties desired. With the advent of methods for the investigation of high-molecular-weight proteins, polypeptides, polyketides, etc., it is now possible to enter entirely new fields and to study more complex materials derived from plant, animal and other sources. It is here that future developments, coupled with the possibility of more specific targeting, hold most promise for the beneficial utilization of otherwise highly poisonous substances.