Recently, the influence of various origins fats on the morphofunctional and biochemical characteristics of the organism has been actively studied, however, their possible influence on higher nervous activity and behavior has been mostly overlooked. The aim of the research was to study the dynamics of behavioral changes in rats after the long-term consumption of fats differing in origin. The behavior of adult male rats was explored by the open field test for three days on the basis of the indicators of their research and emotional activity after 60 days of consumption of fats of various origins (palm oil, refined sunflower oil, margarine) at a rate of 3 mg/kg. The obtained experimental data show that when rats consume fats differing in origin for a long time, their navigation research behavior in terms of horizontal and vertical activity and the number of hole visits does not differ significantly, both when retested in the open field and compared with the control group. However, it was found that their emotional activity (according to the manifestations of autonomic reactions of defecation and grooming) has changed as the prolonged consumption of used fats causes a change in the level of anxiety in male rats. The long-term consumption of palm oil is accompanied by a tendency to increase bowel movements as well as the number and duration of grooming acts, both in re-testing and compared with the control group. The male rats that had consumed margarine for a long time, on the contrary, demonstrated a decrease in the level of anxiety. In comparison with the control group and during testing, they showed a reduction in the manifestations of grooming and defecation. During three days of observation, the indicators of emotional activity of the rodents that had consumed refined oil for a long time stayed almost unchanged and did not differ from those of the control group.