To observe the clinical picture of zinc phosphide poisoning, 120 mammals (pigs, sheep, goats, calves, rabbits, dogs and cats) were administered a zinc phosphide preparation in doses of 10-150 miligrams per kilogram. In most cases the symptoms of poisoning developed rapidly, culminating in a fatal outcome in a matter of hours, and signs of poisoning were similar in all species of experimental animal used. The animals first experienced short-term stimulation, manifested by unrest, whining, dashing or leaping about the cage etc, followed by depression giving way to paralysis of the extremities. Total loss of appetite, vomiting (in pigs, cats and dogs) arythmia of respiration, tachycardia, bradychardia, hypothermia and a terminal comatose state gave further evidence of zinc oxide's injurious effect upon the animals' nervous systems.