Animals are constantly exposed to a wide variety of foreign chemicals, many of which are potentially toxic and some of which result in the clinical poisonings. Pesticides are applied on or around animals for the control of insects and rodents. These chemicals may be placed in areas without regard for accessibility to household pets and domestic livestock. Insecticides, herbicides, and fungicides are routinely and haphazardly applied to animal and environmental surfaces alike with apparent disregard for differences in absorptive capability. Fortunately, newer herbicides and fungicides are relatively nonhazardous. Drugs are considered to have therapeutic effects, but the lay and professional person's disregard for species differences and variations in recommended dosages can result in poisonings. Adverse reactions may be misnomers for errors in judgment. Failure to provide satisfactory storage facilities for animal feeds and the improper preservation and handling of feedstuffs allow the growth and development of a variety of mycotoxins. Ignorance on the part of animal owners and livestockmen can result in a number of unusual and sometimes fatal clinical syndromes. The dependence of domestic animals and livestock upon their owners for the total environment makes these animals extremely susceptible to environmental pollutants. Exposure to noxious gases, irritating and hazardous industrial materials and wastes, water contaminants, and casually discarded compounds of our own use can and frequently do result in animal illnesses and death. Persons responsible for animals may be unaware of the potential hazard or lack good judgment in the use of these chemicals. Forceful and continuing education for the safe and sensible use of all foreign compounds on and around domestic animals and livestock is needed. Persons handling and applying these materials must recognize their responsibility, not only to themselves but also to their neighbors and the animals in their care.