Psychobiological basics for the formation of self-killer organisms are considered in this paper, which, according to the presented opinion, is due to serotonin deficiency as a result of malnutrition. It has been shown that serotonin deficiency is revealed in the organisms of those children who show aggressiveness towards animals and in those monkeys who have lost their leadership in own herd. For the prevention of the aggressiveness it is desirable as to eat food products rich in tryptophan as food additives-a serotonin precursor amino acid-red caviar (100g/790mg), black caviar (100g/710mg), Dutch cheese (100g/790mg), melted cheese (100g/500mg), etc.