ABSTRACT
Toxic substances have always been used by many species of animal including humans for defensive and offensive purposes. Textbooks of pharmacology are full of examples of such agents used by man, e.g. arrowhead poisons such as digitalis from Strophanthus and curare from Strychnos and Chondrodendron. Although there are many examples of man using natural toxins for his own purposes there are probably many more of one animal species using toxins to control another, to deter an attack by another, to immobilise a food source either for immediate or later consumption. Pharmacology has a rather positive image being concerned with the treatment of disease by natural products, structural modifications of natural products and by synthetic drugs designed for treatment of a particular disease. In contrast, toxicology is sometimes regarded in a negative way. This is a misconception, for in its wider context natural toxins have a respectable position in evolutionary development which has allowed the equilibrium between species to be attained and maintained. Man-made chemicals also have provided and will continue to provide protection by the control of disease vectors (in many species) and also enhanced comfort, convenience and security in modern society. Toxicology and pharmacology are complementary and the thought processes involved in mechanisms of toxicity are similar to those in pharmacology.
