The purpose of this course is to describe the toxicity in connection with the environment. First of all, it introduces the definition and classification of toxicants, the factor of toxicity, the procedures of first aids, and principles of antidote. These are the bases of self-protection and emergence solutions. Secondly, the course also introduces the characteristics of toxicants available everywhere in the air, water, and soil. The contents are resources of toxicants, characteristics of both physical and chemical, toxicity, important poison events and proper application of antidotes. In addition, it also in introduces the important toxicants, pollution of food, and industrial poisons. So the students would further learn about these toxicants to prevent both acute and chronic exposure.