Studied was the preparation diazepam-pulvis for suspension (DPS) with regard to its tranquillizing and myorelaxing doses, inhibiting the aggression, and preventing the stress conditions in domestic animals and birds. It was established that at oral application to pigs at rates of 1 to 2 mg/kg body mass DPS produced a pronounced tranquillizing effect, while at 3 mg/kg it led to myorelaxation as well. In sheep tranquillizing effect was seen when amounts of 3 to 5 mg/kg body mass were used, and myorelaxation was achieved with 6.6 to 13.2 mg/kg. In male calves tranquillization was manifested after doses of 3 mg/kg body mass were applied. In hens the tranquillizing dose was found to be 3 mg/kg body mass, and the myorelaxing one--4 mg/kg; in cocks the respective doses were 5 and 7 mg/kg body mass. At the rate of 3 mg/kg body mass DPS was found to enhance the thiopental-sodium narcosis. When offered to pigs at 2 mg/kg body mass in admixture with the feed DPS led to tranquillization and suppression of the active and passive defense response. No full prevention of cannibalism could be achieved. The daily administration in the course of 30 days with the ration of bull-calves at the rate of 3 mg/kg body mass was shown to calm the animals under loose housing in boxes and affect favourably their weight gain. Admixed with the feed of cocks at 5 mg/kg DPS suppressed aggressiveness.