Background: The present study investigated the influence of diumancal and decursinol on the level of monoamines and products of lipid peroxidation within the different brain structures (hypothalamus, frontal cortex, striatum) and the importance of presynaptic and postsynaptic parts of catecholaminergic system of the brain in their mechanism of action. Material and methods: The study was conducted on 520 white male rats, 150-220 g weight. The substances were administered intraperitoneally in the following dosages: diumancal – 0.1 mg/kg; 0.5 mg/kg; 1 mg/kg; decursinol – 1 mg/ kg; 5 mg/kg; 10 mg/kg and verapamil – 5 mg/kg; 15 mg/kg. Results: The study revealed that diumancal and decursinol have dose dependent, two-phase action: in low dosage they activate, while in high dosage they suppress behavioral activity of rats. The use of pharmacological analyzers (cлонидин 0.05 мг/кg, апоморфин 0.1 mg/kg; 1 мг/кg, a-methyltyrosine 200 мг/кg, propranolol 15 м/кg) allowed to reveal the importance of pre- and postsynaptic catecholaminergic mechanisms of the brain in the mechanism of action of diumancal and decursinol. During trials both drugs increased serotonin level in hypothalamus, corpus striatum and frontal cortex, decreased norepinephrine in hypothalamus and frontal cortex and dopamine in corpus striatum. The level of dopamine in hypothalamus and frontal cortex decreased after administration of low doses of diumancal and decursinol and did not change under the influence of high doses. Conclusions: Diumancal and decursinol decrease the formation of products of lipid per oxidation, increased during stress, and possibly have antioxidant action.