INTRODUCTION

Toxicology is concerned with the deleterious effects of chemical and physical agents on all living
systems. The terms poison, toxic substance and toxicant are synonymous. The most important
axiom of toxicology is that “the dose makes the poison”, indicating that any chemical or drug can
be toxic if the dose or exposure becomes high enough. Poisoning occurs by non-therapeutic
substances such as household and environmental agens, and due to over-dosage of
therapeutic substances. Poison may be ingested accidentally or deliberately. A difficult
challenge to the health care provider is the identification of the toxicant and limited availability of
antidotes. Thus, the health care provider in most cases, may be limited with symptomatic
therapy.
“Treat the patient, not the poison” remains the most basic and important principle of clinical
toxicology.
A toxic response can occur with in minutes or after a delay of hours, days, months or years.
Acute toxicities are of particular interest for practicing health care provider.